US2617593A

US2617593A - Counting and grouping device

Info

Publication number: US2617593A
Application number: US577481A
Authority: US
Inventors: Audier Mark; Edwin W Seeger
Original assignee: Cutler Hammer Inc
Current assignee: Cutler Hammer Inc
Priority date: 1945-02-12
Filing date: 1945-02-12
Publication date: 1952-11-11
Anticipated expiration: 1969-11-11

Description

NOV. 11, 1952 AUDIER ET AL 2,617,593

COUNTING AND GROUPING DEVICE Filed Feb. 12, 1945 3 Sheets-Sheet l DISTANCE DISTANCE OF 23 STEPS OF l5- STEPS NOV. 1952 M. AUDIER ET AL ,617,

COUNTING AND GROUPING DEVICE Filed Feb. 12, 1945 3 Sheets-Sheet 2 Nov. 11, 1952 M. AUDIER ETAL COUNTING AND GROUPING DEVICE 3 Sheets-Sheet 5 Filed Feb. 12, 1945 A 5 Al zotqziifi Patented Nov. 11, 1952 COUNTING AND GROUPING DEVICE Mark Audier, Milwaukee, and Edwin Sceger, Wauwatosa, Wis, assignors to Cutler-Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Application February 12, 1945, Serial Na-$77,481

(owes-132) 3 Claims. 1

The invention relates to improvements in counting and grouping devices, and, while not limited thereto, is particularly applicable to the counting and grouping of newspapers as they are carried on a belt conveyor from the press to a receiving station.

In the production of newspapers, it is customary to provide a counter Iortotalizing the papers produced by the press adjacent to the belt which carries the folded newspapers to a delivery station. The counter is customarily actuated by a lever or the like so that upon the passage of a paperthe lever is oscillated to move the counter forward by one number. It hasalso been proposed to connect with said counter, a device which is actuated each time a certain desired number of papers has passed the counter to displace the last of s-aidnumber of papers, so that the total number of papers between two displaced papers represents a standard lot of, say, twenty-fiveor fifty papers, which may then be taken oiT the belt at the receiving station to be bundled into standardpack'ag'es.

Newspapers are delivered to various distributors in individual bundles, each bundle containing a difierent number of newspapers, depending upon the requirement of the respective distributor. To expedite the delivery of papers and to reduce the amount of work of preparing them for shipment, it is desirable to provide means which automatically group the desired number of papers for therespectivebundles, and an object of the presentinvention is to provide means for such grouping.

The devices, which have been used heretofore for counting the total number of papers produced, are inaccurate because their time of response is too great in-relation to the speed with which the papers pass by the counting device. Hence the speed of the press and the speed of delivery of papers from the press had often to be limited by thespee'd'of registration of the available counting devices.

An object of the present inventionis to provide for a greatly increased speed of response of the counting device, so thatthe press and the delivery belt can be operated at their maximum speed without affecting the accuracy of the paper count.

The accompanying drawingis illustrative of certain embodiments of the invention.

In the drawing,

Figure ,1 represents diagrammatically a counting device: incorporating the invention,-while Fig. '2' is a detail or certain parts of Fig. l.

2 Fig. 3 is a modiflcatipn of certain parts of the system shown in Fig. 1. t I I Fig. 34 is a diagram of certain voltage variations in t e system il t ated i ma Fig. 5 is a modification of the system's shown in Figs l to 3.

Fig. ,6 is a, graph of the action of the system H inFig.5. M v

'Fig'. 7 is adetail drawingof the control switch f r the sy t m shown in w l es. 1 .1 .3- 7

Referring to 1, 2 and 7 the same illustrate a conveyor belt J0 ofany suitable conventional type which moves in the direction of the arrow and on which a series or folded newspapers I are disppsed inshiplapfashion, so that they move with the .belt with the fold trailing h' 'b l y ,Q ihe 9 E911, Above the b 1t,.soas to c r e p ssin vp' p,ers., a ranged a sin lepole, double-throw switch 12, which is shown in detail in'Figfi, I i

As shown in .Figx'i, the switch i2 comprises a h em hichar finsula ed vm te a stationary contact i2, a yieldingly supported upper stationary contact I2, and an intermediate movable contact I2, which ,isbiase'd to engage the contact [2% The movable contact i2 is provided with a contact shoe [2 which projects outside of the casing. The casing is r e it o wa d en w th a d w w projection l2 of such length, that normally the shoe 12 extends slightly'below the projection 112 "The switch as a wholeis supported on the frame of the conveyor by a leaf spring 122 which normally forces the shoe 12 and theprovjection I2 into contact with the papers passing thereunder in such a way that the contact I2 engages upper contact 12'. At the moment when the trailing edge of a newspaper leaves the 10 .1 wh l he proje t o J i still in contact withsaid edge, the shoe 12 moves downwardly, thereby causing contact 12 to disengage contact I'Z and engagecontact l2, as shown in detail ;in Fig. '7. .A mfomentlater the projection 12 also drops downjon the next pap r ,,.t eby causing .td s neasl n vof co tact 12 from cont'act l 2 and engagement of thesf ormer with contact 12*. s

p The switch 12 controls the current supplied froma suitable sonrfce L L to a pair .o'i electroma gnets l3 and II. having energizing windings i3 and l-l respectively. Eachoneof the electromagnets i3 and H is arranged adjacent to an arm 15?, and 15, respectively, of. adouble-end'ed pawl t5, which is mounted in cooperative relation to a ratchet wheel It. The ratchet wheel is provided with ten teeth and the arrangement is such that for each complete oscillation of the ratchet I5, the ratchet wheel rotates through an angle equivalent to the distance between successive teeth in a counter-clockwise direction. The ratchet wheel 56 is driven by a torque motor I! of any suitable type through a tension spring 18, one end of which is connected to the shaft H of the torque motor, while the other end is connected to the shaft IQ of the ratchet wheel 18. When the ratchet wheel is standing still the spring 58 is tensioned in accordance with the maximum torque exerted by the motor 11, and when the wheel is released upon oscillation of the ratchet l5, the spring It! causes a quicker oscillation and movement of the ratchet wheel to its new position. The introduction of the spring between the motor and the ratchet wheel I6, greatly reduces the time lag which otherwise would be high on account of the inertia of the rotating part of the torque motor ll. Coupled to the shaft E9 in any suitable manner so as to rotate in synchronism, therewith and at the same speed, is a shaft which has attached thereto a cogwheel Zi provided with five equidistant cogs in its circumference. The shaft 20 is further provided with an extension 2 i which through a suitable positive gearing drives a conventional counting device 22, provided with a number of dials. One revolution of the pointer of the right-hand dial corresponds to ten revolutions of the ratchet Wheel It; the pointer of the center dial makes one revolution for every one hundred revolutions of said wheel 16, etc. There is also connected to the shaft 2!, by gearing or in any other suitable manner, a shaft 23 which rotates at the same speed as the shaft 20. The shaft 23 carries a disc 26 of sheet metal or other opaque material and is provided with ten holes numbered 1 to 9 and 0, the holes being arranged around the disc at equal angular intervals from each other in the natural order, 1 to 9, followed by 0, and at distances from the center decreasing in equal decrements in the following order: 1, 8, 5, 2, 9, 6, 3, 0, 7 and 4.

Arranged in parallel with and adjacent to the disc 2 1 is a strip 25 of opaque material. This strip is of a width somewhat greater than the radial distance between the holes 1 and 4 on the disc 24 and its one edge is provided with a series of holes 25. The cogwheel 21 is mounted adjacent to the strip 25, so that the cogs successively engage the successive holes 26 of the strip to move the latter in the direction of the arrow. Thus when the ratchet wheel It rotates through an angle corresponding to one tooth, the strip 25 moves one-half of the distance between holes On the side of the disc 24 opposite to that on Which the strip 25 is mounted is a mask 2'! of opaque material. This mask is provided With a narrow slot 28, of a width slightly larger than the diameter of the holes in the disc 2 A light source 29 (see Fig. 2) is mounted opposite to the mask 21, so that light rays from th sourc 29 may pass through the slot 28 and through any hole in the disc which may be in alignment with the slot. The strip 25 is provided with holes so located. that they selectively are in alignment with corresponding holes in the dis-c 24, when the respective hole in the strip is in the common plane of the slot 28 and the light source. Opposite the side of the strip 25 is mounted a condensing lens 38 (see Fig. 2), so arranged that when a hole in the disc 24 matches with a hole 4 in the stri 25, a light ray from the source 29 impinges upon the lens 30 which focuses said ray upon a photoelectric tube 3!, to thereby vary its illumination with a resulting variation of its impedance.

Adjacent to the conveyor belt It) and in substantial transverse alignment with the switch I2 is mounted a spraygun 32, which is adapted when actuated to spray a small quantity of a colored liquid on one of the passing papers. As illustrated in the drawing, the spraygun comprises an outer conduit 32 and an inner conduit 32 The ends of the two conduits are concentric and in close proximity to each other to form a nozzle. The inner conduit is connected to a suitable liquid container 32, while the outer container is connected to a suitable source of compressed air, and the admission of such air is controlled by a normally closed valve 32 which in turn is actuated by an electromagnetic winding 32. When the winding 32 is energized air pressure is admitted to the spraygun. The air issuing from the nozzle produces a partial vacuum which sucks the colored liquid into the air stream with which it mixes to be deposited on the paper.

The illustration of the spraygun is merely diagrammatic, its construction being no part of this invention and any suitable electrically operable means for spraying a colored liquid on the paper or of marking it otherwise may be employed. The winding 32 has one of its terminals connected to the anode 33 of an electron tube 33, which is also provided with a cathode (i3 and a control electrode 33. The second terminal of the winding 32 is connected through a resistor 34, to the positive terminal of a direct current power supply, such as a storage battery 35. The resistor 34 is paralleled by a condenser 35. The cathode 33 is connected to the negative terminal of the source 35. The control electrode 33 is connected to one terminal of the photoelectric device 3| and is also connected through a resistor 31, to the negative terminal of the source 35. The second terminal of the photoelectric device 3! is connected to the positive terminal of the source 35.

The operation of the spraying device is as follows: When counting is to begin, the hole in the disc 24 and the first hole in the strip 25, corresponding to the numeral 0, are aligned with each other and with the light source 29, and the photoelectric cell 3i. Assuming that the counting of newspapers is to start with 0 and that the first bundle should contain twenty-three newspapers, the ribbon 25 is then provided with a hole which as indicated in the drawing will match the hole 0 in the disc when the hole in the ribbon is opposite the slot 28. A second hole is punched in the ribbon which is so located that it will match the hole corresponding to the numeral 3 in the disc, the lateral spacing from the first hole in the ribbon being such that the disc 24 makes 2.3 revolutions between the matching of the first and the second hole. If it is further desired that the second bundle should contain fifteen papers, 2. third hole in the strip 25 is spaced from the second hole by a distance corresponding to 1.5 revolutions of the disc 24 and a corresponding travel of the strip 25.

When no light from the source 29 impinges upon the photoelectric cell 3!, the potential of the control electrode 33 is such that the tube 33 conducts little current so that the coil 32 is not sufficiently energized and the valve 32 is closed and no colored fluid issues from the spraygun 32.

germ-3 When light impinges upon the photoelectric cell 31 the control electrode 33 becomes more positive thereby rendering the tube 33 more conducting. In the interval during which the photoelectric cell 3 I is not illuminated the current flowin through the tube and through the 0011.32 while insufficient to produce a pull which will open the valve 32 is sufiicient to charge the condenser 36 to a minimum potential so that ii the impedance of the tube 33 is decreased upon illumination of the photocell 3 l, the condenser'charges at a high rate through coil 32 to pull the valve 32{ open, and thereby cause colored fluidto be discharged on the paper. However, as soon as the condenser 35 is fully charged its current rapidly drops to a value which permits the valve 32 to close again, so that the spraygun delivers'c'oljor fluid only for a very brief interval, the length of the interval being determined by the constantsof the circuit already described.

As the magnet 44 is normally energized the ratchet arm IE is in the position shown, where it makes contact with a tooth of the ratchet wheel 16. The ratchet wheel is thus prevented from rotation. As soon as the paper starts moving past the switch Hi, the circuit between the contacts l2 and i2 is broken by the raising of the shoe lE This causes deenergization of the magnet l4, resulting in the release of the arm l of the ratchet 45. At substantially the same instant the contact l2 engages the contact I2 thereby energizing the magnet [3 to attract the ratchet arm i5 which releases the ratchet wheel from the arm [5 to permit rotation of the wheel and moving the ratchet arm l5 into engagement with a tooth of the ratchet wheel thus permitting'the wheel 46 to move one-twentieth of a revolution. As soon as the paper has passed the switch I2, the magnet l 3 is again deenergized and the magnet !4 is energized thereby moving the arm l5 out of engagement with a tooth of the ratchet wheel 18 and again moving the arm l5 into the path of another tooth of the ratchet wheel I6, permitting the ratchet wheel to move another one-twentieth of a revolution and thus completing one step of the escapement. As successive papers continue to pass under the switch l2, the ratchet wheel continues to rotate, the driving power being supplied by the torque motor I l through the spring l8, as has already been described. Rotation ofthe ratchet wheel l6 causes rotation of the cogwheel 2| the disc 24 and the counter 22 in synchronism with the ratchet wheel. Rotation of the cogwheel 2| a moves the strip 25 with a step by step motion in the direction of the arrow until after twenty-three operations of the switch 12, the ratchet wheel l6 and the cogwheel 2W, the disc 24 has rotated 2.3 revolutions. At that moment the second hole punched in the strip 25 matches the hole corresponding to the numeral 3 in the disc 24 and a ray of light from the source 29 impinges upon the photoelectric cell 3|, thereby energizing again the coil 32 to spray colored liquid on the paper which at that moment is under the spray gun 32. Thus the total number of papers from the first to and including the marked paper is twenty-three, and they may be removed together as a bundle. The apparatus continues to function as described until the third hole in the strip 25 matches the hole in the disc 24 corresponding to numeral 8, which occurs after an additional fifteen oscillations of the ratchet l6. Thereupon another paper is marked in the manner described and the bundle of papers between the first and inclusive of the second marked paper fifteen. Thus by proper punching, the strip 25 may be arranged so that theli'ntefval between any two a marked papers corresponds to any desired number. '7 I H In additior'ite marking the papers sdas to divide them into individual group itis also desirable to count the total number of papers deliverd. This is accomplished by the counter 22 in the usual manner, as will be cibviou s.

Fig. 3 is an improvement of the circuit for controlling the solenoids f3 and I4 of. FigI 1 and' is especially for extremely high speeds. Inthe circuit shown in Fig. 1,- the contacts of the control switch l2 must carry the entire energizing current for the coils l3" and l4 and under certain conditions may be subject to considerable arcing. Furthermore, while the; movable parts of switch 12 are light they have some inertia and, especially under high speed operatingconditions. may be subject to chattering, thus possibly causing inaccuracies in counting. The interval during which the coil [4 is ener i ed depends upon the duration of engagementbetween the contacts 12 and l2 and if thespeed is high the period of closure ofthe energizing circuit forthe coil M may be insuificient. The ratchet must make one complete oscillation for each passingpaper.

The diagram (Fig. 3) illustrates a means whereby the operation of the device is improved. for high speed installations. Instead of. energizing the coils l3 and I4? directly through a circuit, including the contacts-of the switch [2 an amplifying circuit is interposed. The ratchetwheel lfi of 3 is provided with only 5 teeth, instead of 10, asin'Fig. 1. a

In this modif cation the pivot of. the ratchet I5 is supported by a permanently magnetized bar l5, which produces poles of one polarity in the arms [5 and [5 ofthe ratchet I5, while the cores [3? and l4 are of the'opposite polarity. The coils I3 and Hl are so connected that the current flowing; therein induces magnetic fields in the cores I3! and [4 which tend to make the twopole faces of the cores of opposite polarity relative to each other. Hencethe magnetic flux of one pole face' is increased and. that of theother is weakened-and with a'current; of suitable magnitude is reversed to the samepolarity as that of the associated ratchet arm, with the result that said arm is repulsed, while, the other armis attracted. The" effect of each core upon the adjacentrratchet" arm reverses with reversal of the currentin the coils l3 and I 5*. The combined efiec't-of the magnets on the two lever arms greatly increases the power available for oscillatingthe arm and thereby makes the oscillations of the latter more positive. This permits increasing the speed of operation of the ratchet mechanism; shown in Fig. 3 over that obtainablewith themechanism shown in Fig. 1. Direct current is suppliedfrom the lines L and L The system includes a pair of electron tubes 49 and having cathodes 4'O and M respectively,

anodes

40 and 41*, respectively,

control electrodes

40 and 41, and

screen grids

40 and 41; respectively. The cathodes4li and M? areeach connected in series with resistors 42 and 43, respectively, to the movable contact l2 of the control switch 12. The anodes 40 and M are connected through resistors 44 and '45, respectively',-to' the positive line L 9. A condenser 3-9 is connected betweenthe anodes '41]? and H The control grids 40 and 4 U are connected through

resistors

46 and 41, respectively, to the stationary contacts l2 and 12 respectively. The contacts l2 and [2 are further connected through

resistors

48 and 49, respectively, to the negative line L The movable contact I? is connected through a resistor 55 in parallel with a condenser l, to the line L The

resistors

32 and 43 are paralleled by

condensers

52 and 53, respectively, while the screen grids 40 and M are connected to the corresponding cathodes; 45 and M respectively.

The system also includes a pair of

gaseous electron tubes

54 and 55, having

cathodes

54 and 55, respectively,

anodes

54 and 55", respectively,

control grids

54 and 55, respectively, and

screen grids

54 and 55 respectively. The

cathodes

54 and 55* are jointly connected to the

screen grids

54 and 55 and are further connected through a resistor 56, to the line L The control grid 54 is connected through two series connected resistors 57 and 58, and the control grid 55 through similar series connected

resistors

59 and 60, to line L Connected in series with each other between the common terminal of the resistors 51 and 58, and the common terminal of resistors 59 and 6H3 are two condensers of like capacity 6| and B2. The common terminal of the condensers 5i and 62 is connected to the cathode ll The

anodes

54 and 55 are connected in series with

resistors

63 and 54, respectively, to the end terminals of the center tapped primary winding 65* of a transformer 65, which is also provided with a secondary winding 65*. The center tap of winding (55 is connected through a limiting resistor 56 to the line L. The secondary winding 55 and the windings Id and M are connected in series to form a closed loop. Connected between the

anodes

54 and 55 is a condenser 61.

The system as described thus far operates in the following manner: Referring to Figs. 1 and 3, with the conveyor l6 and the switch E2 in the position shown in Fig. 1, the circuit is closed between the contacts w and 12. Under these conditions the grid 3! has a potential which renders the tube ll conducting and a current flows from line L, through resistor 55, the tube 4|, resistor as through the resistor 50 to line L The constants of this circuit are chosen so that the voltage drop across the resistor 55 impresses a potential on the grid 45 with respect to the cathode 46 which renders the tube 45 non-conducting. When upon motion of the conveyor Ill, circuit between the contacts i2 and I2 is broken, and circuit is made between the contacts l2 and l2, the grid A0 has impressed thereon the potential of the oathode in which causes the tube 45 to become conducting, and due to the current flowing through said tube a potential drop appears across the resistor M, which lowers the potential of the anode 45 to charge the condenser 39 in a manner to also lower the potential of the anode 41 so as to render the tube 4| nonconducting. The purpose of the

capacitors

52 and 53 is to delay decrease of the potential of the associated cathodes long enough to allow the corresponding anode potential to decrease sufficiently so as to extinguish the respective tube.

The operation of this part of the circuit shall be further explained in connection with Fig. 4. The tubes 40 and ti with the condenser 39 constitute a multi-vibrator circuit. In the past it v has been customary to employ the potential variation of the anodes of the tubes to afford a controlling effect. In the present system the varying potential of the cathode is used to produce this controlling effect and the effect can thereby be made much more precise. It will be apparent that when the tube ll is non-conducting while the tube 10 is conducting the potential of the cathode di is somewhat above that of the bus bar U The value of the cathode potential is indicated by P in Fig. 4 and depends upon the voltage drop in the resistors 42 and 50, produced by the current passingthrough the tube 40. If now the tube 4i becomes suddenly conducting the potential of the cathode ll increases to the value P such increase taking place almost instantaneously, the only delay being due to the time necessary to charge the small condenser 53. As long as the potential of the cathode 4! had the value P the potential of the grid 5 3 was that of the bus bar L The sudden rise of the potential of thev cathode di from P to 1? impresses a transient charge upon the condenser 5!, and the potential of the grid 54 is correspondingly raised temporarily from that of bus bar L to a more positive value as indicated by the dotted curve V Thereafter the potential P remains constant for an appreciable period so that the potential of the grid 56 again drops to that of the bus bar L During the next period when the tube 35 again becomes non-conducting and the tube becomes conducting the potential of the cathode (i l drops again from 15 to P the change being slightly retarded again by the action of the condenser 53. This causes a negative potential V to be impressed upon the grid 54 but this negative potential is obviously incapable of effecting the conduction of tube 54. It will thus be seen that by this circuit arrangement a transient potential of a relatively high peak value and unilateral polarity is impressed upon the

tubes

54 and 55 resulting in a very precise and positive control of said tubes.

The potential change of the cathode M due to the alternate conduction and non-conduction of the tube i! is thus impressed, as aforedescribed, upon the control grids 5 3. and 55 through the capacitors 5i and 62, respectively. Assuming that the tube 5'1 is conducting, it is apparent that its grid 5 is biased negatively by a voltage which is equal to the drop through the resistor 56. When the tube M becomes conducting the positive potential of the cathode H increases by an amount which is equal to the drop across the resistor 33. As the cathode di becomes more positive it also makes the grids 5 3 and 55 more positive. As long as the tube 5a is conducting it is not affected by this increase, but as the tube 55 is non-conductingthis increase in its grid potential causes the tube to become conducting. Similarly if the tube 55 is conducting, an increase in the potential of the grid 54 causes the tube 54 to become conducting which in turn through the action of the condenser 57, in a Well known manner, extinguishes the tube 55. The alternate conduction of the

tubes

54 and 55 causes pulses of current to flow alternately through the two halves of the winding 55 and this current induces an alternating current in the windin 65 which flows alternately and in opposite directions through the coils l3 and M As the magnetic system operating the ratchet I 5 is polarized the alternating current flowing in the coils l3 and I i causes the ratchet to oscillate alternately from one position to the other upon each current 9 pulse in the winding 65 thus permitting the ratchet wheel 16* to advance upon each pulse onehalf of the tooth pitch. The frequency of oscillations of the ratchet is thus one-half of that shown in Fig. 1. The operation of the balance of the system is the same as described heretofore in connection with Figs. 1 and 2.

Fig. shows a modification of the system illustrated in Fig. 3, only such elements being shown as are necessary for an understanding of the changes required. The resistor 45 of Fig. 3 is replaced by a biasing battery 46, having its positive terminal connected to the control electrode 40. Furthermore, the control switch i2 is elimihated and is replaced by a photoelectric cell NH. The photocell NH has its positive pole connected to the common terminal of the

resistors

47 and 39, while its negative terminal is connected to the control electrode 32 of a high vacuum electron tube Hi2, which is also provided with a cathode |02s and an anode ic2 The anode M2 is connected to the common terminal of the battery 46 and the resistor 48 while the cathode W2 is connected to the negative terminal of the photoelectric cell lol, through a resistor i 03. A source of direct current voltage I94 for supplying current to the photocell it?! is connected to the positive terminal of the photocell I EM and to the cathode I02 The illumination of the photocell HM in response to the movement of papers through the recording zone is controlled in the following manner: A light source I95 is mounted above the con veyor belt It in such a manner that at the zone of reference the light strikes the papers obliquely, as indicated by the dotted lines. In consequence the trailing edge of each paper casts a deep shadow upon the adjacent surface of the succeeding paper as the papers successively pass through said zone. The photocell IOI is provided with an enclosure Hil which shields it completely from any light, except for a light beam which may pass through small orifices lfll and NH arranged on the axis of the photocell. The orifice t is preferably arranged in a partition mounted within the enclosure transversely to the axis of the photocell while the orifice llil may be arranged in the wall of the enclosure Mil The photocell assembly is mounted in such a way that the axis is directed toward the point at which the papers are to be counted. The light beam refiected by the papers and which impinges upon the photocell MI is normally a maximum. However, when the shadows on the papers pass the axis of the photocell the intensity of the light beam is greatly reduced so as to substantially reduce the conduction of the photocell.

The modified system illustrated in Fig. 5 functions in the following manner: Inasmuch as either the tube 40 or the tube ii is conducting, the voltage drop across the resistor 56 has a given value the resistor terminal closest to the cathodes 40 and M bein positive with respect to the resistor terminal connected to line L When the photocell ml is illuminated with maximum intensity the voltage drop through the

resistors

43 and 49 is a maximum. In that case the tube H is conducting while the negative voltage on the control electrode 43 which is the resultant of the voltage drops through the resistors 50 and Q8 and the battery 65 is a maximum.

Normally the light intensity on the photo-tube I0] is maximum so that the control electrode 132 has a maximum positive potential. Hence the conduction of the tube 192 is also a maximum.

As a result, a current flows from the source let, through the resistors 59 and 58, through the tube I82, back to the source I94. The voltage on the grid 40 is equal to the resultant of the voltage drops through the

resistors

59 and 48, and the opposing voltage of the battery Mi If now the intensity of the light beams reflected by the papers and impingin upon the tube it! is reduced, the positive potential of the control electrode N32 is also reduced, thereby reducing the current passing from the battery I84, through the

resistors

8 and 49. The decrease of the voltage drop through the resistor 48 reduces the blocking potential on the grid 66 until a value is attained at which the tube ii becomes conducting. The initiation of current conduction in the tube 153 causes the interruption of conduction through tube 4 l as has been explained in connection with Figure 3, and the potentialof grid 41 changes to a value which is equal to the voltage drops through the resistors 5d and If the intensity of the light impinging upon the photo-tube lei again increases, the voltage drop through the resistors Q9 and 48 again increases so as to raise the potential of the grid 49 to a value to again render the tube as conducting and the cycle will be repeated. It will be observed that upon initiation of conduction of these tubes 45 or ll the

condensers

52 and 53 and their coacting resistors 52 and d3 momentarily depress the potential of the cathodes of the respective tubes to insure positive action of the circuit. The varying potential of the cathode ll" causes alternate conduction of the tubes and 55 as heretofore explained.

Fig. 6 illustrates the response of the system to the variations of the intensity of illumination of the photocell in Fig. 5. It is well understood that the illumination of the photocell by the light source is subject to modifications by unwanted external light and by variations of the reflective quality of the paper. Furthermore, there may be other factors besides the movement of the objects through the light beam impinging upon the photocell, which tend to vary the alternate conduce tion of the tubes 45} and 4! in response to the movement of the objects. These influences would cause unwanted response of the tubes 49 and ii and would lead to faulty indications. By proportioning the circuit, particularly the resistors d8, 49, and the voltage sources thi and I64, the circuit may be arranged so that after being nonconductingthe tube ll does not become conducting again until the intensity of illumination of the photocell lili passes from a value lower than A in Fig. 6, to a higher value as indicated by the arrow C. The aforedescribed response is not affected to any substantial degree by fluctuations of the voltage supply. After the tube 4| has thus become conducting, the current of the photocell may vary, as indicated by the curve, either above or below the value A, and the tube it will not become conducting to extinguish the tube 4! until the illumination drops below the value B as indicated by the arrow D in Fig. 6 whereupon the tube 4% becomes and remains conducting even though the illumination of the photo-tube varies below or above said value B, except if it should increase again to the value A. In the latter event the tube 4i again becomes conducting as indicated by the arrow E. It will also be noticed that any minor variation in voltage of the source Hid will not substantially aifect the relation of the voltage drops in the resistors 48 and 69, and thus the response of tubes 43 and H is substantially unaffected by such variations in voltage. It will 1 1 also be seen that the circuit may be designed for any desired sensitivity to variations in illumination of the photo-tube, such sensitivity being substantially unaifected by variations of the voltage supplied to the photocell circuit.

We claim:

1. In a system for grouping, by marking, articles moved in succession through a given zone. in combination, a rotatable disc provided with a plurality of apertures arranged at regular angular intervals and at difierent distances from the center of said disc, a program ribbon provided with a plurality of apertures arranged to co-act, upon movement of said ribbon, successively with certain of said first named apertures for permitting passage of a beam of light through the co-acting apertures, a counting mechanism comprising means constantly tending to move said disc and said ribbon, said counting mechanism further comprising means responsive to movement of each article through said given zone to control said first mentioned means for operation intermittently in equal steps and in synchronism with the movement of the articles, a photo-cell responsive to illumination by said beam of light, and means responsive to control by said photocell for marking the articles completing the predetermined groups.

2. In a system for grouping, by marking, articles moved in succession through a given zone, in

combination, a rotatable disc provided with a plurality of apertures arranged at regular angular intervals and at different distances from the center of said disc, a program ribbon provided with a plurality of apertures arranged to co-act, upon movement of said ribbon, successively as desired, with certain of said first named apertures to permit passage of a beam of light through the co-acting apertures, a counting mechanism comprising control means responsive to movement through a given zone of a series of articles to be grouped, an escapement including an oscillatable member, a co-acting ratchet wheel and means for rotating said ratchet, electromagnetic means responsive to said control means for operating said oscillatable member, driving connections from said ratchet wheel to said disc and to said ribbon for moving them in synchronism with movement of the articles, a photo-cell responsive to illumination by said beam of light, and means responsive to control by said photo-cell for marking the articles completing the predetermined groups.

3. In a system for grouping, by marking, articles moved in succession through a given zone, in combination, a rotatable disc provided with apertures arranged at regular angular intervals and at different distances from the center of said disc, a program ribbon provided with a number of apertures arranged to co-act, upon movement of said ribbon, successively with certain of said first named apertures for permitting passage of a beam of light through the co-acting apertures, a first photo-cell responsive to illumination by the beam of light, means responsive to control by said first photo-cell for marking the articles completing the predetermined groups, a pair of electron tubes, means to direct a beam of light on the moving articles for reflection thereby and for variation by each article in passing through a given zone, of the intensity of the reflected light, a second photo-cell subjected to the reflected light and responsive to variations in its intensity, means for initiating conduction of one of said pair of tubes upon illumination of said second photo-cell increasing to a given relatively high value and for initiating conduction of the other of said pair of tubes upon the illumination decreasing to a given relatively low value, said means including means for rendering the first mentioned tube non-conducting upon the other tube becoming conducting and vice versa, an escapement including an oscillatable member, a co-acting ratchet wheel and means for rotating said ratchet wheel, electromagnetic means responsive to the conduction of said tubes for operating said oscillatable member, and driving connections from said ratchet Wheel to said disc and said ribbon.

MARK AUDIER. EDWIN W. SEEGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,366,938 Renz Feb. 1, 1921 1,403,182 Maturin Jan. 10, 1922 1,444,505 Hathaway Feb. 6, 1923 1,548,102 Sherman Aug. 4, 1925 1,753,961 Zworykin Apr. 8, 1930 2,030,624 Ek et a1. Feb. 11, 1936 2,137,013 Bradley Nov. 15, 1938 2,162,508 Knowles June 13, 1939 2,170,157 Pray Aug. 22, 1939 2,299,272 Hallden Oct. 20, 1942