US2675916A - Electronic inspecting apparatus - Google Patents

Description

April zo, 1954 R. H. CASTON ET AL ELECTRONIC INSPECTING APPARATUS Filed June 28, 1949 6 Sheets-Sheet 1 April 20, 1954 R. H. cAsToN ET A1. 2,675,915

ELECTRONIC INSPECTING APPARATUS Filed June 28, 41949 6 Sheets-Sheet 2 April 20, 1954 R. H. cAsToN ET Al.

ELECTRONIC INSPECTING APPARATUS 6 Sheets-Sheet 5 Filed June 28, 1949 s Y m. mm m m m N CA T E VIL T V RN. A w, mw /m HL D/ H L f ww BAW. W Ew 5mm o n Cu Nw Y l L x ,B d m WN f AS N Q9 NQS La@ L r mm n wm l l S: d l 1 Nn ov om mw #n nm "l l A f3 WIN m61 April 20, 1954 R. H. cAsToN ET AL 2,675,916

ELECTRONIC INSPECTING APPARATUS Filed June 28, 1949 6 Sheets-Shea?l 4 RALPH HENRY GASTON BY LOWELL WALLACE ZABEL ATTORNEYS April 20 1954 R. H. cAsToN ETAL 2,675,916

ELECTRONIC INSPECTING APPARATUS 6 Sheets-Sheet 5 Filled June 28, 1949 24L r Agg-afbouw me I L u POWER P-HOTO AMPLI 56) A zeezgzEN 'e ZG Suzpgu ma; F'ER saS STAGE 22 a3 57) el; Pow=n SUPPLY I2 62) 24e swoozm le@ e5 l 24d HG1 ss/f DOZEN coNTRoLLme RELAY sers 24a 24a 24,: 24h 24a l2 l `H WE mi] [iL-DEE @El E EASTMAG.

INVENToRs RALPH HENRY GASTON LOWELL WALLACE ZABEL ATTORNEYS APU] 20, 1954 R. H. GASTON ETAL ELECTRONIC INSPECTING APPARATUS 6 Sheets-Sheet 6 Filed June 28, 1949 Qmz maorllil OION. @2522 or 5.0 z. Pzn. mmmod mmww zmNoQ DE.;

ON. mvzz ...ku z. P25.. mmmgo um mmmmf. zmNon. ozooum O l mm @z ozi C,...

0.7.5.0 z.. .v2.01 mumq .0.51m O... omhuuzzoo .m2 .3. .om

INVENTORS. o N RALPH HENRY GASTON g LOWEL MLLACE ZABEL 9' a BY n /am/y @M077 ATTORNEYS Patented Apr. 20, 1954 ELECTRONIC INSPECTING APPARATUS Ralph Henry Caston and Lowell Wallace Zabel,

Neenah, Wis., assignors tcvlnternational Cellucotton Products Company, Chicago, Ill., a corporation of Delaware Application .time z8, 1949, serial iva-101,892

(ci. 20s- 74) 7 Claims.

rThis invention relates to the high-speed manufacture of articles which prior to sale, or prior to packaging are assembled in sets, groups, or stacks each containing a plurality of said articles. As any incident to such manufacture, it may be desirable, for various reasons, to cull out or select for special treatment certain of these assemblies. For example, a change in characteristics or an abnormality in one of the supplied ingredients or components of the articles may be the basis for such selection.

This invention is of especial value in connection with an automatic arrangement for effecting the high-speed production of soft and compressible articles, such as a plurality of sanitary napkins and the like fromcontinuous rolls of gauze-like material, which articles are assembled in stacks or packages. Particularly, the invention relates to inspecting apparatus for use witha'n arrangement of this general type, which is operative to inspect the gauze-like material prior to its use in the manufacture of the individual sanitary articles, and as a result of such material inspection, to segregate the stacks of completed napkins which are found to be defective from those napkin stacks which are found to be acceptable.

In one arrangement of'automatic apparatus used in' the manufacture of articles of this general type, the independent pad-making and stacking units are spaced apart and deposit stacks of pads into individual buckets or receivers carried by a single, common conveyor unit. The conveyor and associated buckets in turn deliver packaging equipment. An installation of this preferred general type is disclosed in a co-pending application of Jones and Banks, Ser. No. 92,424, which was filed May 10, 1949.

In the manufacture of the gauze material such as is used in the pad-making equipment described, it is customary in thetextile mills to mark defects or splices in the gauze by means of a series of black stitches'or a section of black tape, applied to the gauze at the point of defect or splice. Such markings are, of course, undesirable in any articles which are intended for sale.

It is, therefore, a general object of this invention to provide automatic and positive-acting means for inspecting the gauze, detecting portions of the material which are marked as defective and rejecting articles made of such defective material. 5

In the manufacture of certain articles, such as the stacked articles to suitable LBO sanitarynapkins, kof Awhich one part comprises a gauze-like lmaterial folded about anapkin body, some of the gauze surfaces become inaccessible for inspection afterthe article Lis completed, and for this reason theinspection of the gauze is desirably made prior to its` inclusion in the individual articles. Although the inspection is necessarily made at such timeto insure the detection of each marked portion, the contemporaneous removal of-such portion is considered somewhat impractical by reason of the highspeed operation of the automatic pad-makin equipment. f ,d

In View of these considerations, a further object of the invention is to providean apparatus for use in the manufacture of. sanitary napkins, which is operative to. inspect the continuous strip of gauze before it is folded around the pads to detect any defective portion, and toinitiate `the operation of a mechanism which Will reject the articles made from suchdefective portion, but

not until after the articles have been` included in a stack. Y

Other objects and advantages of the. invention will be Aunderstood Aby .reference to the following .specication yand accompanying drawings (6 sheets), in which we have described and illustrated a preferred embodiment ofthe mechanism for effecting the inspection and rejection of defective sanitary napkins.

In the drawings,

Figs. la and 1b, when placed adjacent each other, .illustrate sideelevations of the automatic pad-making equipment and the inspecting apparatus of the invention, y

Fig. 2 .is aschematic illustration of the operating elements of theautomatic :pad-making apparatus, l. y

Figs. 3 ande, when arranged yin side byside relation, illustrateothe circuit diagram of the inspecting vunit of. the invention,

Fig. .5a is an end View of thetiming mechanism of the inspecting apparatus, and Fig. 5b is ay front View of the same mechanism which includes broken away portions to more clearly illustrate certain details thereof.

Fig. 6 is a schematic illustration of the circuit layout for the inspecting unit which especially shows the arrangement of the individual relay sets-of the control unit,

Fig. 7 is a schematic illustration' showing the travel` path of the successive 'pad groups as manufactured,the accompanying' legend properly identifying the contrllingrelay 'set for each napkin stack in e'achfcycle, and

-' travels around suitable rollers or drums 4.

Figs. 8, 9, and 1l are diagrams which illustrate the effective operating times of the timing mechanism cam units of the inspecting apparatus.

GENERAL DESCRIPTION The `general arrangement and functioning of the inspecting apparatus of the invention asapplied to sanitary napkin making apparatus may be best understood by reference to Figs. 1a and lb of the drawings. As shown there, a cyclic sanitary napkin making machine comprises pad making and wrapping apparatus A, wrapper cutting apparatus C, end tab folding apparatus D, and cyclic stacking or article-grouping apparatus E, which may be of the general type shown in the co-pending application heretofore mentioned. The pad making and wrapping apparatus A embodies a table I over which a strip of gauze 2 is drawn from a source of gauze supply in the form of a roll, such as 3, by a conveyor belt which A continuous web of wadding material (not shown) is fed transversely of the length of table a-nd pad sections of the proper width are cut `from the web by means of a reciprocating cutter unit 5. The width of the pad cut from the web is substantially less than the width of the gauze strip and such pad is deposited approximately centrally of the moving gauge by means asso- Succesciated with the cutting mechanism 5. sive pads are deposited in longitudinally spaced relation on the gauze strip. At least one of the margins of the gauze which project beyond the 'side edges of the deposited pads passes beneath an inspection device 6 as said gauge travels through the machine.

Said margins are folded longitudinally around the pads as they progress along the indicated path of travel, thereby forming a continuous string of gauze connected sani- I tary pads. The gauze connected pads are propelled from the pad making apparatus A to the rotary cutter C. The gauze between the adjacent ends of the spaced pads is severed at the proper intervals from the pad ends by means of a rotary knife 1 in the cutter C and the independent pads are thereafter deposited on a conveyor 8 of the folding apparatus D which folds the gauge end flaps over the gauze wrapped pad portions. The folded napkins are discharged by the folding apparatus D to a conveyor I0 of the stacking apparatus E and said conveyor I0 feeds the pads -into a pad receiving and stacking means |31. In

this instance, twelve napkins successively delivered to said stacking means constitutes a full stack. livered from said stacking means alternately to storage compartments II and I2 of the apparatus as represented in Fig. 7. A pair of horizontally reciproca-ble plungers, one of which is represented at I 38 in Fig. 1b, are provided for al ternately delivering the napkins stacks from the stacking means |31 to storage compartments I and I2. From the said storage compartments,

the napkin stacks are normally discharged to buckets on a receiving conveyor I3.

As explained in detail in the aforementioned 2o-pending application, triggers such as indicated at I3@ (Fig. 1b) are mounted on the bottom of each of a series of bucket members on said conveyor I3, each trigger depending from its bucket member so as to be operative incident to its travel with its bucket, to actuate one of a pair of switches |312 or I3f (Figs. lb and 4). which are mounted on the stationary conveyor framework I3c. As switch I3b, for example, is operated by a Successive dozens of napkins are depassing trigger, the contacts of such switch are closed to normally complete an electrical circuit I3dJ (Fig. 4). The electrical circuit I3d as thus completed, extends from a battery over or through the winding of a slave or separation control relay I4, switch IB, switch I3b, and switch 86 to ground. (In the diagram Fig. 4, a source of power for operating various parts is indicated as one or more batteries for purposes of simplicity. In actual practice, the batteries would be replaced by connection to a suitable source of power such as indicated at 6I and 62 in Fig. 3.) Slave relay I4 is thus operated and its switch I1 completes an energizing circuit for a solenoid I8 which, on operation, opens the bottom gates I9 of the compartment II through suitable linkage members (Fig. 1b) to effect discharge of a napkin group or stack from said compartment .II to said receiving conveyor I3. The cam triggers are arranged beneath the buckets to normally alternately actuate the gates of the storage compartments II and I2 to eiect delivery of the contentsA of said compartments to the receiving buckets on the conveyor.

In the event that the napkin group or stack in the compartment (compartment for example) includes a napkin made from a defective piece of gauze, the switch 86 in said circuit I3d, will be opened (as hereinafter explained) to prevent delivery of the napkin stack to the conveyor I3 and to effect the subsequent displacement of the defective stack from said compartment II to a reject chute or conveyor 2|.

INSPECTING AND REJECTING UNIT Such circuit operation and napkin rejection is initiated by the inspecting device 6 (Fig. 1a) which is arranged to examine the moving gauze as it passes over the table I of the pad-making machine said inspecting apparatus comprises a photoelectric tube unit 22, an amplifier unit 23, a memory or registering device 24, and a suitable power supply unit` 25.

. The power supply unit is adapted to be energized over two main power supply leads 28 and 29 which are connected to a suitable power source 26 (such as a 11S-volt 60 cycle alternating current source), on closure of a switch means 21.

`The power supply unit essentially comprises a transformer member 30 and a series of networks 3 I, 32, and 33, respectively, connected across supply leads 28 and 29 so as to supply positive and negative potentials of various values to the tube and relay elements of the phototube unit 22, amplier unit 23, and memory device 24.

The phototube 22, which may conveniently comprise any commercially available, highvacuum phototube, such as the RCA number 929. is normally mounted adjacent an interrelated light source 43. Suitable mounting means (not shown) allow focusing and positioning of the light source relative to the material being inspected to insure proper functioning of ythe unit in operation. The anode of the phototube is connected to supply lead 44 and positive voltage is supplied to the anode by network 3| which includes selenium rectifier 34, and voltage divider 40 which comprises a fixed resistance 40a, a variable resistance or potentiometer Mib, and a condenser or capacitor 3l'. The cathode of phototube 22 is connected to the power supply lead 29 through a load resistance 45, which is in the order of 4.7 megohms, and is also connected to the control element of the rst tube .l in the amplifier unit 23 by a condenser 46.

.gemein '5 amplifier `uitrit hilly' oheniel'fltly cnpilse 'a 'pair Soi electronic'tubes "41 and 48 electrically interconnected so as to be operatively controlled by 'predetermined output 'signals of the' phototube 22.

The first electronic tube 41 in the amplifier unit may conveniently comprise a detector am- 'plifler pentode tube, such as RCA tube number 9001, or any other similar type 'am'pliiier tube. The plate of the amplifier tube 41 is connected to supply lead 44 through resistance 49, which may be in the order of .V27 megohm, whereby positive voltage is supplied to the plate by network 3I. The control grid o`fV the amplifier tube 4'1 is connected to said v'adinet-'able resistance 401) in the voltage divider network 3| by means of grid resist-or 58, and positive bias potential is 'supplied 'th'ereover by network '3| torender the tube 41 normallyconductive. The grd of tube 41 is furtherV connected fao-the cathode circuit'fthe phototube 22 through condenser 48, V'the amount of conductivity of the amplifier tube41 being determined by voltage `changes 'the cathode circuit of the kphototube 22.

The sensitivity of response of the tube 41 to variations in the phototube cathode circuit may be controlled by adjustment of the variable 'potentiometer 40h, the value of the Vbias voltage supplied to the grid oi amplifier 41 as a result of the adjustment of the potentiometer 40o directly aiiecting the amount of voltage change required in the photctube cathode circuit to overcome such bias and to effect the desired conductivity of amplifier tube 41. The resistance 40o inthe preferred embodiment is adjustable to values which produced la bias voltage of between 0 and'4'3 volts.

The conductivity of tube 48 is controlled responsive to variations in the voltage values oi' the plate circuit 0f amplifier tube 41, which are 32 which comprises rectifier 35 voltage divider 4I and filter capacitor 38. The network 32 is connected to the amplifier grid over conductor Sla and grid resistance 52. The plate of thyra- .tron tube Mi is connected to the network 33,

comprising selenium rectiiier 36, illter capacitor Y39, and resistance 42, by means of conductor58, one or more of the relay windings 80-0, l|5-O, 90-0 or 12S-O, conductor 51, and resistance e58, whereby positive voltage is supplied by the Inetwork 33 to the plate of thethy'ratron tube 4 8. A neon tube 55 whichmaybeof'the conventional type is connected across leads 56 and 51so as to be operated responsive to striking of ampliiier tube 48 and the result-ant' potential drop across resistance'58 'and one or more of the aforementioned relay windings. A resistor 54 connected in series withthene'on tube 55 is operative as a current limiting resistor therefor.

The plate circuit of the thyratrn tube is thus connected to the memory device unit 24 over resistance 58 and conductor 51, whereby each energization of the plate circuit effects similar energization of' the liritei'coIiriected members in the memory'device 24. A condenser 1582:, Which mayk be in the ordr f 16 microf'arads. is cn- 6 nect'ed in 'series with 'a resistance 58 which may be in the 'order of -50 ohms, and the series 'arrangement is connected between the plate and` YIn normal operation of the amplier stage, however, an amplified signal is automatically transmitted 'to `the memory device 24 over conductors 516 and 51 with each passage of a defective portien through the inspection zone in a manner to be described hereinafter, the manual switch being employed in the event the operatordesire's to reject a selected group of pads for examination or some other purpose.

The memory 'or registering device 24, as shown in Figs. 6 and 4, may be viewed as comprising four similar and separate relay sets 24a, 24b, 24e and 24d which are energized over a common supply set of conductors Bland 62 by the main control switch 26. Actually the number of relay sets employed may be variedin accordance with the particular application of the device, at least two sets being desirable for proper functioning of this type arrangement. Each of the relay sets is arranged to be selectively connected to rthe phototube 22 and amplifier stage 23 by cam controlled switches 83, 64, 65, and 66. Each of the switches 63, 64, 65, and 66 is I'controlled to close separately and in sequence (Figs. 8, 9, 10, and 11') each being arranged to close substantially for the period -that the material for a dozen napkins `passes beneath the inspection unit 6. Since the switches are continuously recycled in the saine order, and there are four switches, each relay set is connected to the amplifier once with the passage of the material for each four dozen napkins, Vand each set, 'as a result of such cyclicl connection, is associated with a predetermined dozen lof each of four dozen napkins.y For example,

switch 6'3will be closed and relay set 24a will be connected to the amplifier 23 and the phototube 22', as the material iorthe rst dozen napkins of each four dogen napkins to be manufactured passes the inspection apparatus 6. Relay sets 24h, 24e, and 24d will be similarly connected by 'successively operated switches 64, 65 and 68 as to vavoid unnecessary,r duplication of the operating members.

In one embodiment, each relay set, as for examplerelay set 24a, may comprise a memory or separation initiating relay 88 having an operating winding 811-0 arranged to be connected in the plate circuit of thyraton tube k4i! by contact 63 for a given period in each cycle of four dozen napkins and a reject relay 85 having an operatirig winding 85-0 controlled in its operation with the'iirst dozen napkins of each cycle by the switch '8`2'of memory relay 88. Memory relay 80 and reject relay /8'5 are of the standard two-winding',

mechanlcaL latch-up type relays which mechan- `icallyv lock theirswitch contacts in the operated `position on energization of the primary windings 80-0* or 85-O and unlock their said contacts in response to energization of the secondary or release windings BIl-R and 85-R. Operating circuits for the release windings of relays 80 and 85 are respectively controlled for operation with the iirst dozen napkins of each cycle by contacts vswitch 88 in the circuit of winding SII-R and switches 89 and 9| in a circuit with winding 85-R.

The normally closed switch 86 of reject relay 85 is in the control circuit |3d for the solenoid.I |8 to allow normal operation of the gates |9 of compartment whenever the contained dozen `are acceptable. Should the napkin group be defective, switch 86 will be opened in a manner to -be described, and the gates will be prevented from operating, thereby to temporarily retain the abnormal group or stack of napkins in the i :storage compartment I.

Each of the relay sets 24h, 24o and 24d may be similar in arrangement and operation to relay fset 24a, each relay set being adapted to control Van individual reject relay such as 85, connected in the operating circuit, I3d for the gates of .storage compartment I I. .third dozen napkins in this arrangement are However, since the stored and delivered by the same compartment Aas the iirst dozen of each cycle (i. e. by compartment II), a common reject relay, such as 85, may be used for the rst and third relay sets (24a `and 24e) to control the operating circuit for the gates of said compartment and a reject relay |20 which is common to relay sets 24h .and 24d may be employed for controlling the gates |9a of compartment I2, thereby to minimize the number of separate operating members .required in the control system.

Accordingly, in the preferred embodiment, re-

.lay set 24e which controls acceptance of the third dozen napkins is interconnected with relay set 24a. Relay set 24e comprises an indi- ,vidual memory relay 90, of the described mechanical locking type, which has its operating circuit 99-0 connected to the thyraton plate circuit by switch 65 whenever gauze material for the third dozen napkins of a cycle passes the inspection unit. Switch 9| of memory relay 90 is .arranged to control a second operating circuit for the operating winding 85-R of the reject relay 85 to control the delivery of the third dozen and cam controlled switch 95 and switch 8| of memory relay 80 control said second operating circuit for the release winding of reject relay `fk5-R. A release circuit for memory relay 80 is controlled by cam controlled switch 94.

Relay sets 2412 and 24d are interconnected in .a manner similar to that of relay sets 24a and 24o and are operative to control the acceptance and rejection of the second and fourth dozen which .are stored and delivered by compartment I2.

In Fig. 4, in the apparatus for operating the gates |9a, the elements designated |411, |6a, 1a

and ISa respectively correspond in function to j .the elements designated I4, I6, I1 and I8 for operating the gates I9.

`and 92, correspond respectivelyA to kthe elements SII-R and 82 of memory relay 80. In the memory relay |25, the elements |25-R, |26 and 21 respectively correspond to the elements Il-R, 8| and 82 of the memory relay 80.

A timing mechanism 10 comprising a series of cam actuated switches is employed for sequentially connecting the four relay sets to the amplifier unit. This timing mechanism 1I) (Figs. 5a and b) comprises a cam shaft 1| synchronized in its rotation to the speed of the paid-making machine by a reduction gear arrangement generally shown at 12 (Fig. lav). In the present embodiment, the cam shaft 1| is driven by gear arrangement 'I2 at the rate of one revolution for the passage of each four dozen pads beneath the inspection unit. The shaft 1| mounts a series of cams at spaced intervals along its length, the outer periphery of each cam having a cam lobe such as 1S, which is disposed to contact and operate a pair of cooperatively mounted microswitch units which are interconnected in the operating circuits for the above described relay sets. One of the said cams, indicated at 15, cyclically and independently connects each relay set 24a and 24e to the ampliiier stage 23 for a predetermined interval in each operating cycle. The remaining cams designated |00 to |05 respectively, are similarly associated with pairs of switches in circuits as shown in Fig. 4 and said teams are timed to operate in accordance with the cam-operating diagrams illustrated in Figs. 8 to 1l, inclusive, to effect the other relay operations as hereinafter explained.

STANDBY CONDITION Prior to placing the automatic pad-making apparatus into operation, power supply switch 21 for the power pack unit 25 is closed to energize the heating elements vof the various tube units in the amplifier stage with a voltage in the order of 6.3 as obtained from the secondary of trans'- former 30. The light source 43, which is also energized by the transformer 30, is adjusted so as to eiect proper focusing of the light output relative to the inspecting zone through which the gauze material is arranged to pass in its movement. The White surface of the gauze is effective to reflect the radiant light energy output of the adjusted light source to the sensitized cathode of the phototube 22 to cause the cathode to relsponsively emit electrons within the phototube body. The emitted electrons are drawn to the Ipositive plate or anode of the tube to thus renthis time.

OPERATION As the starting switch (not shown) for the automatic pad-making machinery is closed, the movement of the gauze beneath the inspection unit 6 will be effected and the white surface of the moving gauze material will reflect the radiant energy of the light source to the cathode of the phototubeunit 22 to render the tube contin- 9 uously conductive. Power Vtake-ofi memberson the pad-making machine A drive the reduction gear unit 12 andthe cam shaft 'II at a` predetermined rate ofv speed to effect operation of the inspecting equipment in synchronism with. the moving gauze.. As shown in Figures a, 5b and 8, in the initial operatic-n of shaft "Il, cam 15 is effective to operate micro-switch 63 to close Iits contacts for the rst quarter of the shaft revolution. Since the shaft makes one revolution with the passage of each four dozen napkins, memory relay 80 is thus connected in the plate circuit of thyratron tube 48 over conductors 56 and 5`|r andY micro-switch 63 for the period that the gauze for the first dozen passes the. inspection unit.

(a) Travel of an` acceptable dozen As the gauze moves beneath the inspecting unit, fluctuations in. the. light reflecting vcharacteristics vary the amount o f radiant energy reilected to the phototube 22.. Instantaneous changes in. the value of current passingv through the loald resistance are effected with such variations and. are` transmitted; in the form of voltage changes through condenser 46 to the control grid. of the first amplilier'tube 4l. Voltageychangesin theV positive direction ,dueto increasedV reflection` of; the whitev gauze material will. have; little eiecton the. positivelybiased. am.- I

plier. tube 41... Small voltage variations in the. nega-tive. direction will. likewise have little effeet., on. amplifier tube 41;,.and if. the material for the ilrst.. dozen napkinsisr acceptable, that. is, does notincludeblack markings of'. the described.v type.,no `fiutthercircuit operation will. occur, Microfswitch; 63.: will beopened-by cam 15..to disconneet the-relay. set.i2.4a; from the thy-ratron circuit as the portion of` thezmaterial. to be used inv the. seconddozen enters the inspectionzone. and-relay set: 24h isin turn connected. to the thyratron. plate circuit` by. cam. actuated. switch 6.4. The electrical-1 control circuit i3d: associated with relay set 24a..is subsequently completed by closing of: switch I.3b by the passingv cam. trigger I3a, whereby solenoid I8 operatesiandv the gates I3 of' compartment I I. arexopened. to eiect deposit of the rst'.. dozen napkins intoV its assigned" bucket.

(b) Travelof ar defective dozen Assuming, however, that the gauze for theiirst dozen is defectiveandV carries a black string or tape in the manner described,- as the black' marking passes throughv thel inspection zone, theamount of radiant energy. reflected-to the` phototube.A cathode by the gauze material; is suddenly` decreased, andthe. electron emissionof the .cathode: of". phototube 22` is.A correspondingly.` reduced;

instantaneous current. change in. the negatlve;direction appearsa-cross the load resistance 45 which is transmitted as..-a. negative voltage iluctuation through condenser 46 to the control grid of amplifier tube 41. 'I'he conductivity of tube 4.1is accordingly decreased-to effect a--voltagechangeat the plate .of tube 41 which is'trans.-V mitted over condenser 5I to the grid circuit of' thyratron tube 48. The grid of the--thyratron tube 48, which is normally biased to cut oif by the negative voltage supplied overV g-rid resistanceA 52 and network- 32, is made morepositive bythe-- positive voltage change in the -plate circuit of i the`- tube 41 to effect increased-conductivity lofI thyratron tube 48- and energization of thn-thyratron plate circuit.

Memory relay 80, which-is presentlyconnectedin; the thyratronf. platecircuit byy closed switch 63, is operated' by a circuit extending from the positive side of` the network 33 over conductor 56, micro-switch 63, the primary or operating coil Slt-Ooi relayll, conductor El, resistor 53 and the conducting thyratron tube 48, to the negative side of network 3.3:.. Neon tube 55, being connected across conductors 56. and 5l in series with resistance' 54,. will strike responsive to the potential drop across resistor-58 and the operating winding. of relay 80-0 as the' operating circuit to the. primary winding. 80'O of relay 8l) is completed'. A. visual. signal is thus provided for the operator to indicate, the presence of a defect in the material passing; beneath the inspection unit at that. time.

Relay operates... and at its switch 8l opens a point inthe. operating circuit. for the release winding 85-R of relay 35, and. at its switch 82 prepares an operating circuit for the primary or operating'winding 85-0 of reject relay 85. Relay 80, in. operatingmechanically locks switch 82 in-fthe closed .position through associated mechanical means (notshown).

Thyratron tube 48 is de-energized almost immediately following its energization, by meansof a resonant circuit comprising condenser 58a, resistancel 59 and theprimary coil of relay 80. The resonantcircuitis shock-excited to. oscillation by the firing ofthe thyratron tube 48,and the values of' the circuit are so selectedv that during the negative half cycle of. the timed circuit oscillation, the plate voltage-of the thyratron tube 48 willbe decreased to a value sufficient. to effect extinguishing of the thyratron tube. The operatingy circuit for the primary windingo-f relay is: thus immediately de-energized to prepare the amplifier for subsequent operation'. The relay switch; 32. of memory: relay 80` is maintained closed by the describedmechanicalllocking means to: indicate a-defect-in the gauze for the first dozen-napkins.

If furtherI defective-portions-are detected in the gauze -sectionfor the rst dozen, the phototube 22 and-famplier circuit 23-wil1 be re-operated inthe described manner-'to transmitv affurther signal'tothe primary or operating' winding of relay 80. Such signal will', ofcourse, provide no fur-ther operation-of the relay-set.. Switch 631s. openedasfthe;.material for thefsecond dozen enters the inspection zoneftoy prevent further transmission of-lsignals-.to relay-- 'for this cycle.

The: moving:v gauze section is converted into twelveindividual. sanitary pads in the manner described in the said co-pending application, andl and; ,as indicated in Figure 8, micro-switch: 95. is

closed-.by camr I'IJ2v for a brief angular interval whereby-:an operating circuit-is completed to the primary .winding of reject relay 815. Such-operating circuit` extends from a battery over the primary windingf 85-O through switch 82- and closed micro-switch :to ground.

Rejfectzrelay- 851operates and its-switch 86 opens a point-'inthe-operating circuit for slave relay- I4, anclits-switchtlf completes a` circuit for a signallam-py |305 to-si-gnal the-operator that the dozen presentlyv contained in the storage cornpartrnent--I I fis defective. `Such means may also be-used-to opera-te aL relay' counter in an obvious manner, if desired, to determine the number of napkin dozens which are defective during a given period of manufacture. A brief angular period after energization of relay winding 85-0, microswitch 88 is closed by cam ID3 to effect the energization of the secondary or release winding of memory relay 80. (See Figure 8 of the cam indicating diagram.) The release winding 80-R of memory relay 80 operates and effects release of the mechanical lock for switch 82. The energizing circuit for the primary winding 85-0 of reject relay B is opened by the opening of switch 82, switch 86 of relay 85 being locked in the open position by the described relay mechanical means.

As the cam switch I3b is operated a short time later by its associated bucket tripping lever I3a, the open circuit condition in the operating circuit for slave relay I4 prevents operation thereof and additionally of solenoid I8. The defective napkin stack is therefore temporarily retained in the storage compartment II. As the succeeding napkin group assigned to this compartment, that is, the third napkin dozen of the cycle, is moved into the storage compartment in the normal manner, the defective first dozen remaining in the storage compartment will be engaged by the incoming new stack or third dozen, whereby said defective stack will be forced out of compartment I I to the reject chute or conveyor 2I (Fig, 1b) as an incident to said delivery of said new stack.

Micro-switch 89, which is connected in the first operating circuit for release winding 85-R of reject relay 85, is operated by cam |02 a short interval after the cam shaft commences the second quarter of its cycle and an operating circuit is completed to release winding 85-R. The release winding 85-R energizes to effect the mechanical unlocking of switch 8l, whereby switch 86 is reclosed and the circuit for slave relay I4 is prepared for subsequent operation by assigned cam trigger I3a. I'he relays in relay set 24a are now restored and the set is conditioned for reoperation in the next cycle if necessary.

In each cycle of operation, the disposal of each of four successive stacks or dozens of napkins is controlled successively by the relay sets 24a., 24h, 24e and 24d, in the manner in which the disposal of the first stack is controlled by said relay set 24a as above explained. These four relay sets are successively placed in operative relation to the circuits which control the operation of the discharge gates I9 and I9a 0f thestorage compartments I Iand I2 respectively, by the cams 'I5 and IIlI and the pairs of switches associated therewith.

OVERLAP OF SELECTOR CAMS Actually, as shown in Figs. 8 to 11 inclusive. switches E3, 64, 65 and 66, which prepare the relay sets for sequential operation, overlap each other for a slight angular period of the shaft revolution. Such overlapping of the cams is utilized to provide means for effecting rejection of two dozen napkins wherever a defect is detected in the material at the dividing point of the gauze used for two successive dozens. For example, if the last portion of material used in the manufacture of the first dozen or the first portion of material used in the manufacture of the second dozen is found defective, relay sets 24a and 24b will both be operated by the signal received from. the amplifying circuit 23 and the phototube 22 over simultaneously closed switches 63 and 64.

The following table illustrates in detail the sequence of operation of each relay in each set as a defect is discovered in the particular dozen which the set is assigned to control. Additionally, it sets forth the cam movements and switch operation which effect the selective and successive operation of the relays described.

TABLE-OPERATION IN ONE CYCLE RELAY SET INTERCONNECTIONS As shown in the table, reject relay is used for effecting rejection of the first and third dozen napkins and reject relay |28 is used for effecting rejection of the second and fourth dozen. Dual use of these relays is effected by the provision of parallel operating circuits extending between relay sets 24a and 24e, and between 24h and 24d.

Operation of the interconnected sets, if the first dozen and third dozen of the same cycle are both defective, is accomplished as follows. Reject relay 85 will be first operated (to effect rejection of the first dozen) over the operating circuit completed through the primary winding B5-O from battery, over closed switch 82 of memory relay 80, and micro-switch 95 to ground. After release of the first dozen napkins into its assigned bucket has been prevented by the operated reject relay 85, and opened switch 86, an operating circuit to the release winding 85-R to effect release of relay 85 is normally completed from battery over release Winding 85-R, switches 9| and 89 to ground. However, since the third dozen is also defective, memory relay will be in its operated condition, and at its switch 9| will have opened a point in the operating circuit for release winding 85-R. Thus, release winding 85-R of reject relay 85 will be prevented from energizing, the switch 81 will be maintained locked closed to indicate the defect, and as the switch I3b is closed by the assigned passing trigger, the electrical circuit i3d will be inoperative and the third dozen will be retained in the compartment for eventual rejection to chute 2|. If the rst dozen in the next cycle are not defective, release winding 85-R of reject relay 85 will be subsequently energized by completion of a second operating circuit extending from battery, over the release winding 85-R, switches 8| and 95 to ground. 'Ihe relay sets 24a and 24e are thus operative to effect rejection of the rst and third dozens, if defective, through use of a single reject relay. The relay sets 24h and 24d are, of course, operated in a similar manner.

SYNCHRONIZIN G UNITS It is apparent from the foregoing that the the half-way `mark in each cycle` The indicating light |35 (Fig. 1b) is arranged to be connected to a source of potential over a micro-switch (not shown) closed as an incident to each operation of a magnetic clutch member |35 on the stacking machine E. Since the magnetic clutch |36 is operated whenever a dozen napkins. are accumulated in the receptacle |31, the indicator light |35 will be illuminated four times for each cycle of the timing unit 'l0 or four times for each illumination of the indicator light |3d. The equipment will be thus properly synchronized if lamp |34. and lamp |35 are illuminated simultaneously at the half-'way mark in each cycle of the inspecting unit.

CONCLUSION equipment. As a result, the production of commercial articles is accomplished in an extremely rapid and sanitary manner. Also, such arrangement, by reason of its inspection of the material prior to its inclusion in the articles, enables lthe unitA to ldetect each of the defective portions in :W

a positive and reliable manner.

The simplicity of the relay circuits, and the various interconnections between the pairs of circuits so as to employ single relays in a dual capacity provides an arrangement which is comparatively inexpensive and which requires a minimum of plant maintenance. The dependability, simplicity and accuracy of the arrangement provides an inspecting unit which is adaptable for use with many types of article producing equipment and is therefore considered a definite advancement in the art.

Various other features of the invention which are believed to be new are set forth in the accompanying claims.

We claim:

1. In apparatus for making sanitary napkins which comprises absorbent pads enclosed in wrappers of sheet material, inspecting means operating on the sheet material components to detect abnormalities therein, means for receiving and assembling the napkins into stacks, means normally operative to receive the stacks from said assembling means, other means for receiving from said assembling means stacks which include sheet material having abnormalities detected by said inspecting means, and means controlled by said inspecting means for causing delivery to said other means, of said last mentioned stacks.

2. In combination with article making apparatus wherein components of articles are fed along a predetermined path of travel and converted to the desired articles by fabricating operations performed successively along said path of travel, the apparatus being such that in the length of said path of travel there are a plurality of articles in various stages of fabrication, means for collecting said articles in groups and holding the groups for discharge from the apparatus, an electric impulse generating device for inspecting cessively connecting the respective relay sets ofv said plurality of relay sets to said discharge controlling relay, saidA last mentioned means. including timing means for delaying actuation of said discharge controlling relay to predetermined times after thev completion of the inspection of said components for successive predetermined groups of articles, whereby time is afforded for the fabrication of said articles. and the collection thereof in groups as aforesaid before impulses generatedV by said inspectingv device are enabled toA effect actuation of said discharge controlling relay.

3. In combination with articlemaking apparatus wherein components of articles are fed along a, predetermined path of travel and converted to the desired articlesby fabricating 12p-` erations. performed successively along said path of travel, the apparatus` beingv such that in the length of said path of travel there are a plurality. of articles in various stagesof'fabrication, means;

successively operable to `collect into grouDS, arti,-l

cles delivered one by one to said means, a pair of holding compartmentsalternatively operative to` receive said groups of articles from said means, means for receiving said articlegroups from. saidy compartments, an electric impulse generating means for inspecting one of the components of each article while in an incompleted stage of fabrication in said path of travel, two pairs of relay sets, a pair of relays for controlling the delivery of article groups from said holding compartments to said receiving means, connections between said relay sets and said pair of relays whereby the relays of said delivery controlling pair are respectively connected to said pairs of relay sets, timing means operative to cyclically connect the relays of one pair of said relay sets to said inspecting means alternately with those of the other pair of said sets, whereby a component of articles'for four successive groups thereof is inspected during each cycle of said timing means, and other timing means in the connections between said relay sets and said pair of discharge controlling relays for delaying actuation of the latter to predetermined times after the completion of the inspection of said components for successive predetermined groups of articles, whereby time is afforded for the fabrication of said articles and the collection thereof in groups as aforesaid before impulses generated by said inspecting device are enabled to effect actuation of said discharge controlling relays.

4. Apparatus for the class described comprising means for feeding articles successively along a path of travel common to all of said articles, means for receiving said articles from said feeding means and assembling said articles in groups containing predetermined numbers of said articles, means selectively operable to discharge said groups from said receiving means in predetermined diverging directions, means for inspecting a part of each article prior to delivery thereof to said assembling means, and means controlled by said inspecting means for effecting delivery of article groups which contain an article having a condition detected by said inspecting means in a predetermined one of said diverging directions.

5. Apparatus of the class described comprising means for combining a plurality of components into unitary articles, means for receiving and assembling said articles in groups, inspecting means acting on a portion of one of the components while such portion remains accessible for inspection independently of other components before combining of the same is completed, and means controlled by said inspecting means for separating from normal article groups, a group which contains a condition detected by said inspecting means.

6. In combination, means for feeding articles successively, assembling said articles into successive groups containing predetermined numbers of the articles, and for temporarily storing such article groups, a conveyor for receiving such groups from said storing means, means for normally eiiecting the delivery of said groups to said conveyor, an inspecting device arranged to inspect a part of each article prior to incorporation of each such article into a group as aforesaid, a relay set operatively connected to said inspecting device for actuation of said relay set as an incident to the passage past said inspecting device of a defective article part, and means controlled by said relay set for preventing the operation of said normal delivery means to thereby cause a group of articles containing an abnormality detected as aforesaid to be retained in said storing means for special, subsequent disposition.

7. Apparatus of the class described comprising means for assembling articles in successively formed Vstacks of articles, a plurality of holding compartments, means for successively delivering to said compartments, stacks of said articles, inspecting means operative in relation to a portion of each article prior to the assembling thereof into stacks as aforesaid, a conveyor for receiving said stacks from said holding compartments, means for normally effecting delivery of the stacks successively from said holding compartments to said conveyor, auxiliary means for also receiving said stacks from said holding compartments, means controlled by said inspecting means for disabling said normal delivery means, said means for delivering the stacks from said assembling means to said compartments being operative as an incident to the delivery of a stack of articles to one of said storage compartments to also eilect discharge from said compartment to said auxiliary means of an article stack containing an abnormality detected by said inspecting means.

References Cited in the 111e 0f this patent UNITED STATES PATENTS

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