US2312357A - Sorting machine - Google Patents

Description

4 Sheets-Sheet l H. T. ODQUIST ETAL SORTING MACHINE Filed March 2, 1940 1 l I I I l ll L-l'l. Ill.

March 2, 1943.

W m6 IQIVII March 2, 1943. H. 'r. ODQUIST ETAL 2,312,357

SORTING MACHINE Filed March 2, 1940 4 Sheets-Sheet 3 3 A l W5 March 2, 1943. H. T. ODQUIST ETAL SORTING MACHINE Filed March 2, 1940 4 Sheets-Sheet 4 l VENTOR 414.22/ 2* 9 4 16 /%2%(F(NE QM a? Patented Mar. 2, 1943,

SORTING MACHINE Harold T. Odquist, Yonkers, and Benjamin Shmurak, New York, N. Y., assignors to American Can Company, New York, N. Y., acorporation of New Jersey Application March 2, 1940, Serial No. 321,990

7 Claims.

The present invention relates to a machine for gauging the thickness of sheet material and for sorting sheets into thickness classifications and has particular reference to a sensitive thickness gauging device utilizing improved electrical circults to more accurately and to more selectively determine the thickness of sheet material and to classify the gauged sheets according to the desired classification.

In the manufacture of containers or cans different kinds of cans are made from materials of different thicknesses in order to obtain the proper degree of strength and rigidity in each can. Such requirements necessitate the use of stock of known thickness and hence requires strict gauging of the stock to insure materials of the proper gauge. Since considerable stock is used in sheet form for these purposes the sensitive gauging of the sheets with known methods adds materially to their cost. Hence approximate gauging methods have been resorted to with the result that batches of sheets sometimes contain sheets which are considerably less or greater than the required thickness and these sheets cause trouble in the automatic machines which convert them into can parts.

The instant invention contemplates overcoming these difficulties by utilizing a highly sensitiveelectric sheet gauging device and amplifying and dividing an electric output obtained in such gauging so that sheet stock of either metallic or non-metallic material and magnetic or non-magnetic material may be rapidly and accurately gauged for thickness and sorted automatically into proper classifications without entailing any great costs.

An object therefore of the instant invention is the provision of a sheet sorting machine wherein electric selector or sorting'instrumentalities are responsve to the electric output of a very sensitive electric thickness gauge device for sheet material so that large quantities of the articles may be quickly and accurately sorted into piles of their respective thickness classification at a minimum cost.

. Another object is the provision of such a machine .which is highly sensitive and uniform in operation and which is free from variation due to vibration of the machine, warpage of the sheets, differences in temperatures and the'like variables of either machine or sheets.

Another object is the provision of a machine of this character wherein the electrical selector instrumentalities are of an interlocking nature so that parts of the gauging operable for a predetermined thickness of sheet will lock out or render inoperative other parts thus insuring more positive and accurate sorting of the articles.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.

Referring to the drawings:

Figure 1 is a longitudinal sectional vir'v of a machine embodying the instant invention, with parts broken away;

Fig. 2 is an enlarged transverse sectional'view taken substantially along the line 2-2 in Fig. 1, with parts broken away;

Fig. 3 is a fragmentary side elevation of the gear train shown at the right in Fig. 2;

Figs. 4 and 5 are enlarged transverse sectional views taken substantially along the respective lines 4-4 and 55 in Fig. 1, with parts broken y;

Fig. 6 is an enlarged side'elevation of one of the control devices used in the machine, the view showing the device enclosed in a housing with its cover removed and with parts broken away;

Fig. 7 is a sectional view taken substantially along the broken line 1-1 in Fig. 6, with parts broken away, but showing the cover;

Fig. 8 is a sectional detail taken substantially along the line 8-8 in Fig. 6 and rotated through an angle of ninety degrees;

Fig. 9 is a wiring diagram of certain electric circuits used in the machine;

Fig. 10 is -a schematic sectional view of certain thickness gauging parts of the machine, the view being taken substantially along the line lfl-IU in Fig. 4 and drawn to an enlarged scale; and

Fig. 11 is an auxiliary wiring diagram of other electric circuits used in the machine.

As a preferred embodiment of the instant invention the drawings disclose one form of a sheet sorting machine for thickness gauging and for sorting metallic sheet material such as tin plate, or black iron plate, or the like material used in the manufacture of containers or cans. In such a machine sheets A to be gauged are conveyed in a continuous procession across a gauging table B (Fig. 1) and pass through a gauging device C of the character disclosed in United States Patent 1,928,457, issued September 26, 1933, to Alfred V. Mershon and Benjamin C.

, Waite, Jr., on Electric gauge.

The gauging device C "sets or initiates the action of a timing delay trip device D as each sheet is gauged for thickness and the gauged sheet is thereupon picked up by a sorting belt conveyor E operating above the path of travel of the sheet. Electro-magnets F hold the gauged sheets in contact with the belt. These magnets are divided into groups, each of which constitutes a sorting station for sheets of a given thickness and when a gauged sheet reaches its proper station "the delay trip device D operates to discharge the sheet at this station by deenerglzing the magnets located there. The sheet thus falls from the conveyor and is received preferably in a hand truck H so that they may be readily carted away when filled.

In this manner unsorted sheets are passed through the machine, gauged to determine their thickness and are then sorted into piles, each pile containing sheets of a predetermined thickness. As an example of such sheet sorting the machine disclosed is preferably provided with four sorting stations indicated by the letters L, M, N, 0. Sheets of (0.008) eight one-thousandths of an inch thick are discharged at the first or L station, sheets of (0.009) nine onethousandths of an inch at the second or M station, (0.010) ten one-thousandths of an inch at the N station, and (0.011) eleven one thousandths of an inch or over at the station. All sheets under (0.008) eight one-thousandths of an inch are preferably discharged from the end of the machine into a separate hand truck.

A detailed description and explanation of the machine will now be given. The various parts of the machine are supported on a main frame ll (Figs. 1 to 5, inclusive) which includes a pair of long side frames l2 tied together by cross beams l3. The gauging table B is located at the entrance end of the machine (at the left as viewed in Fig. 1) and is carried on top of the side frames with its longitudinal edges bolted to the frames. The sheets to be gauged are fed into position on the table in any suitable manner, such as by hand or by an automatic sheet feeding device, conveyor or other mechanism.

Sheets received on the gauging table B are propelled across it in timed and spaced order by a pair of spaced and parallel endless feed chains (Figs. 1 and 4) which extend across the table longitudinally of the machine. The upper runs of these chains operate in grooves l6 formed in the top of the table. The chains operate over a pair of idler sprockets l1 and a pair of driving sprockets IS. The idler sprockets I! are mounted on a cross shaft l9 carried in bearings 2| formed in the ide frames l2.

The driving sprockets l8 are mounted on a drive shaft 22 joumaled in bearings 23 (see also Fig. 2) also formed in the side frames l2. This drive shaft is the main drive shaft of the machine and is rotated in any suitable manner, preferably by a chain and sprocket connection 24 (Fig. 2) carried on one end of the shaft. Feed dogs 25 carried on the feed chains at spaced intervals along their lengths engage behind a received sheet and propel it across the gauging table. Guide rails 21 are secured to the top of the table to maintain the moving sheets in a straight line path of travel.

The gauging device C includes a housing 3| (Figs. 1, 4 and 10) which is secured to the ganging table B adjacent the path of travel of the sheets. The housing supports a rotatable lower gauging roller 32 having a stationary axis and a movable upper gauging roller 33 disposed above the other roller. The lower roller is located in an opening 34 formed in the gauging table 3 and is so positioned that its periphery is flush with or slightly above the top of the table.

, The movable roller 33 is carried on the lower end of a vertical pin 35 which slides in a bearing 36 (see Fig. 10) formed in the housing. The upper end of the pin engages against a sensitively mounted arm 31, of magnetic material. The free end of the arm is disposed between a pair of spaced magnets or electric coils 38 mounted in the housing 3| which are utilized in setting the time delay trip device D hereinbefore mentioned and which are included in certain electric circuits which will be hereinafter explained in connection with the main wiring diagram in Fig. 9.

Hence as a sheet A moves across the gauging table B it passes between the gauging rollers 32, 33 of the gauging device C. In passing between the rollers the upper roller 33 shifts upwardly or separates from the lower roller a distance equal to the thickness of the sheet and this moves the sensitive arm 31. It is this movement that sets the time delay trip device D.

Before describing and explaining the operation of the time delay trip device D it should be observed that a sheet after being gauged for thickness continues on along its path of travel and is brought by the feed chains l5 into engagement with the sorting conveyor E. Since the feed chain dogs 25 are still propelling the sheets during this transfer the latter are maintained in spaced and timed order.

The sorting conveyor E preferably comprises a pair of spaced and parallel endless belts 4| (Figs. 1, 2, 3 and 5) which extend longitudinally of the machine above the path of travel of the sheets. These belts are preferably made of leather or other non-magnetic material. The belts take over a pair of driving pulleys 42 and a pair of idler pulleys 43.

The driving pulleys 42 are disposed adjacent the feed chains l5 and are mounted on a pulley driving shaft 45 carried in bearings 46 secured to the side frames l2. The pulley driving shaft is driven from the main drive shaft 22 by way of a gear 41 which is carried on the pulley shaft 45 and which meshes with a main driving gear 48 carried on the main drive shaft. The conveyor is thus operated in synchronism with the feed chains l5. The idler pulleys 43 are disposed at the discharge end of the machine and are mounted on an idler shaft 49 journaled in suitable bearings secured to the side frames 12.

Between the pulleys 42, 43 and just above the lower run of the belts 4| there is provided a plurality of stationary normally energized electro-magnets 55. The drawings show four pairs of these electro-magnets adjacent the belts, one magnet adjacent each belt at each sorting station. These magnets depend from cross'beams 56 which extend transversely of the machine and which have their ends secured to the side frames 12.

Hence as a gauged sheet A comes adjacent the moving conveyor E it is attracted to the conveyor by the magnets 55 and moves with the conveyor along its path of travel toward the discharge end of the machine. The magnets thus maintain the sheets in their original spaced and timed relation. These magnets also constitute elements for releasing the sheets from the conveyor E at the proper time.

By way of example, when a sheet of nine onethousandths of an inch thickness passes through the roller of the gauging device C the latter sets 2,312,357 the time delay trip device D to deenergize the magnets at station M when the sheet arrives there. With the deenergizing of the magnets the sheet is no longer attracted to thejconveyor belts E and hence it fails away from the conveyor and is received in the hand truck H. There is one of these hand trucks located under each sorting station to receive the sheets as they fall away from the conveyor. i

In such a manner each sheet after being gauged is transferred .to the conveyor E and is discharged attheproper station in accordance.

with its gauged thickness. Sheets under the minimum thickness remain on the conveyor until they reach the end of the machine. Such sheets passover a discharge table 58 (Fig. 1) located at the discharge end of the machine and are introduced by the conveyor into the 'grip of a pair of discharge rollers 59.

The discharge rollers 59 are mounted. one above the other on cross-shafts 60 journaled in bearing brackets GI secured to the machine side frames I2. These rollers are rotated in any suitable manner in timewith the conveyor E. One or bothof the rollers may be magnetic in character if desired. It is these rollers that discharge the sheets from the machine into the last hand truck H: I

Since the machine shown in the drawings is designed for high speed sorting of the sheets, provision is made to strip a sheet which has been released from a magnet station away from the fast moving conveyor belts so that the sheet will not travel along a declining curved path instead of dropping down into the hand truck. This stripping action is brought about by a stripper shoe 84.

There is one oi these stripper shoes I at each sorting station which is located near the center of the station and between the two conveyor belts E. The stripper shoe is formed on the lower end of a vertical rod 65 (Fig. 5). Each rod constitutes a movable core of a normally deenergized stripper solenoid 66 which is carried on the cross beam 56 at that station. Inside the solenoid the core is backed up by the usual compression spring.

The springs in the normally deenergized stripper solenoids 66 hold their stripper shoes 64 above the path of travel of the sheets moving with the conveyor E. This is the normal position of the stripper shoes. However, when a solenoid is energized the shoeis forced downwardly between the belts 4| and against the sheet. It is this movement that ejects or strips the sheet from the conveyor E.

Deenergizing of the electro-magnets 55 and energizing of the stripper solenoids 66 are effected simultaneously by the time delay trip device D which will now be explained. This trip device is located in a covered housing 81 (Figs 1, 6 and 7) which is bolted to the main frame II adjacent the gauging device C. The trip device includes a rotatable disc 68 which is mounted on a horizontal disc shaft 69 journaled in bearings 'II- formed in the housing and in its cover.

The disc is continuously rotated in time with the feed chains I5 and with the conveyor E by a speed reducing train of gears which is driven from the main driving shaft 22. For this purpose a driving pinion I2 (Figs. 2 and 3) is carried on the main shaft 22 adjacent the main driving gear 48. The pinion meshes with and drives an intermediate gear I3 mounted on a short shaft 14 carried in bearings formed in the trip device housing H.- The gear "is formed integrally with an intermediate pinion I5 (see also Fig. 'I) which meshes with and drives a disc gear I0 mounted on the disc shaft 69.

Hence through this speed reduction unit the disc rotates considerably slower than the travel of the conveyor. The timing is such as to effect only a partial rotation of the disc while the conveyor E travels a distance equivalent to the distance between the centers of adjacent sheet sorting stations. This distance is slightly greater than the length of one sheet.

To efl'ect continuous operation of the trip device D the trip disc 68 is divided into equal sectors 03 each one of which corresponds with the partial rotation of the disc for each sheet on the conveyor. The drawings show the disc divided into eight of these sectors. 0n the division lines of the sectors the disc is provided witha plurality of radially disposed rows of short trip pins- There are preferably four of these trip pins numbered SI, 02, 93, 94 in each row of the disc. The pins'are slidably carried in bores 95 formed in radial ribs 00 of the disc held in place by a plunger 91 (Fig. 8 having a pointed end which engages in one or the other of a pair of spaced annular grooves 98 formed in the pins. Each plunger is backed up by a light compression spring 09.

Each trip pin is associated with a particular sheet sorting station in the machine. The outer or first pin 9| is for the sorting station L, the second pin 92 for station M, pin 93 fOr station N, and the innermost pin 94 is for the station 0.

Adjacent and in front of the path of travel of the rows of trip pins in the trip disc 68 is a stationary row of normally deenergized trip solenoids mounted in a plate IOI (Figs. 6 and 7) secured in the trip housing 67. There are four of these solenoids numbered I02, I03, I04, I05, one for each pin'in a row and these trip solenoids are provided with movable cores I06. The four trip solenoids are electrically connected with the gauging device C as will be hereinafter explained in connection with the wiring diagram in Fig. 9.

When a sheet A passes through the gauging device C, the latter energizes the proper trip solenoid at a time when a row of the trip pins on the moving trip disc 68 is directly under the row of trip solenoids. The energized solenoid forces out its core I08 into engagement with the aligned trip pin and thus pushes back or shifts the engaged pin moving in its bore so that it projects beyond and behind the disc further than the other pins in this row.

For example, if a sheet is gauged as nine onethousandths of an inch thick the second trip solenoid I03 will be energized and this will push back the second trip pin 92 in the row which comes into register with the solenoids at the time the Sheet is being gauged (see Fig. 7). The gauged sheet will be discharged at the second station (M) as shown in'Fig. 1. In like manner if a sheet of eight, ten or eleven one-thousandths of an inch thickness passes through the gauging device the latter will energize the corresponding first, third, or fourth trip solenoids and thus set" the first, third or fourth trip pins.

The setting of the proper trip pin for a gauged sheet of given thickness is the initial step or initiating action in starting a time lag or time delay cycle so that the electro-magnets at the proper station will not be deenergized until the sheet has reached this station and is centrally located thereat. In order tomake this time delay efiective there is provided a set of four trip levers III, II2, II3, II4 of diflerent lengths and these are arranged in spaced position adjacent the periphery of the trip disc 68. Each of these levers is mounted on a pivot pin I I6 secured in the housing 61. The inner end of each lever is formed with a lug H1. The outer ends of the respective levers engage against movable elements IIB of double pole, double throw electric switches I2I, I22, I23, and I24. These switches are all connected to the electro-magnets 55 in the stripper solenoids 55. I

Lever III is the shortest of the four levers and is located the distance or one segment 83 of the trip disc 58 away from the row of trip solenoids I02, I03, I04, I05. The' lug 1 on this lever is engageable only by trip pin 9| of a row in the rotating trip disc when such a pin is pushed out or set. All trip pins which have not been pushed out will not engage any of the lever lugs II1. Lever H2 is longer than lever III and is located a space of two segments of the trip disc away from the trip solenoids. The lug II 1 on this lever is engageable only by a trip pin 92 when such a pin is set. In similar manner levers H3. H4 are respectively located a distance of three and four segment spaces away from the trip solenoids and are respectively engageable only by the trip pins 93, 94 when such are set.

Hence when a trip pin is set, the rotating trip disc 68 carries it around in a clock-wise direction, as viewed in Fig. 6, and brushes it against the lever lug II1 which is in the path of travel of the pin. This action rocks that particular lever and hence actuates the cooperating electric switch. Actuation of the switch deenergizes the electro-magnets at the corresponding station and energizes the stripper solenoid at that station thereby stripping the sheet off the conveyor E.

By way of example, when a trip pin 92 is pushed out or set by a sheet gauged to be nine one-thousandths of an inch in thickness, this projecting pin when it reaches the lug II1 of the trip lever II2 trips the lever and actuatesits switch I22. The time it takes the pin after being set to travel from the trip solenoid I03 to the lever I I2 is the time it takes the sheet A to travel from the gauging device C to the sorting station M and it is only when the sheet is centrally located at the station that the trip lever II 2 is tripped and its switch is actuated.

After a set trip pin has performed its function it travels around with the rotating disc and it. with the other pins in the row, passes a reset or return cam bar I25 (Fig. 6). This cam bar is secured in the housing 61 and extends under the trip disc in radial relation thereto. The leading edge is beveled as indicated at I26 and the set pin, projecting beyond the others, rides up on the beveled edge of this bar as the disc rotates. The cam bar thus pushes the pin back into its original position ready to be set" again when required.

Referring now to the auxiliary wiring diagram shown in Fig. 11 it will be observed that the trip switches I2I, I22, I23 and I24 at the correspondthe stations L, M, N, O, and the magnets 55 with the stripper solenoids 55 at each of the stations are connected in parallel with a suitable source of electric energy such as a generator I3I. Each trip switch includes a pair of contacts I32 which are normally closed by engagement with its movable switch element II8. One of these contacts is connected by a wire I33 to a main lead wire I34 connecting with one side of the generator. The other contact I32 is connected by wires I35,

I35 to one end of the electro-magnets 55 at the associated station. The other end of the magnets is connected by wires I31, I38 to a main return lead wire I39 which connects with the other side of the generator.

Each trip switch also includes a pair of normally open contacts I4I. One of these contacts is connected by a wire I42 to the main lead wire I34. The other contact is connected by a wire I43 to the stripper solenoid 66. Each solenoid is also connected by a wire I44 to the magnet wire I38.

Hence under normal conditions, as when a switch is not tripped, electric energy from the generator I3I flows through the closed contacts I32 and through the electro-magnets thereby maintaining them in an energized condition. In this normal circuit the stripper solenoid 65 1s in an open circuit and therefore is in a deenergized condition. As long as the magnets of any particular station are energized the sheets A are held against the conveyor belt E and move through the station.

When a switch is actuated by a set trip pin 9|, 92, 93 or 94, shifting a trip lever III, H2, I I3 or II4, the movable switch element I I9 opens the contacts I32 and thereby breaks the magnet circuit hence deenergizing the magnets. This same movement of the associated switch element H8 closes the contacts I4I at the corresponding station electric energy flows through the stripper solenoid 65 of that station.

It is this sudden fiow of current that energizes the stripper solenoid and thereby operates the stripper shoe. This operation of the switch is only a momentary action sufiicient to perform its function after which it returns to its normal condition with the contacts I32 closed and contacts I4I open. This shifting of current flow reenergizes the magnets and permits them to further function in holding subsequent sheets onto the conveyor E.

As mentioned hereinbefore the delay trip pins 9|, 92, 93. 94 are set by the respective trip solenoids I02, I03, I04, I05 in accordance with the thickness of the sheets A passing between the gauging rollers 32, 33 of the electric gauging device C. The electric circuits attending this gauging device will now be explained and reference should be had to the main wiring diagram in Fig. 9 and to the schematic drawing in Fig. 10.

At the left in the wiring diagram of Fig. 9 there is disclosed a conventional alternating current bridge circuit generally indicated by the numeral I50 and this circuit includes the two electro-magnets or coils 38 which are disposed in the housing 3I of the gauging device C and a differential transformer I5I. The bridge circuit is supplied with alternating current through a supply transformer I52 the secondary of which is connected into the circuit by way of lead wire I53 at a joint between the coils 38 and a lead wire I54 joined to the differential transformer I5I. Two terminals I55, I51 in the bridge circuit are connected to lead wires I59, I59 which transmit the electric output of the circuit.

The electric output of the bridge circuit I5I is controlled by the position of the arm 31 (Fig. 10) between the coils 38. When there is no sheet A between the gauging rollers 32, 33 the arm 31 is in a predetermined position between the coils and there then exists two air gaps I6I, I62 having certain predetermined values which maintain the bridge circuit in a desired initi al'condition.

When a sheet is interposed between the rollera, the movable roller shifts the arm 81 and thereby causes the air gap IN to decrease and gap I82 to increase. This increases the inductance of one of the coils 38 and decreases the inductance of the other coil 38. The change of inductance in these coils changes the output of the bridge circuit.

The change in voltage is approximately proportional to the increased separation of the gauging of the gauging rollers, i. e., the incremental thick-. ness of the sheet being gauged. Therefore thegreater the thickness of the sheet the greater will be the separation of the gauging rollers and consequently the greater will be the output of the bridge circuit. Hence every sheet gauged will cause the bridge circuit to yield a given electric I output and it is this output that is utilized to I9I, I92 and I92 and I93 and in the lead wire] I98 there is provided a pair of filter chokes E99.

of the condensers and between the cross wires The filter circuit iscompleted by a voltage divider system which comprises a cross wire 21 i connecting the lead wire I91 with lead wire I98 and having connected into it a pair of resistors 2I2, 2I3 anda plurality of potentiometers. There are four potentiometers numbered 2I5, 2I6, 2| 1,

actuate selectively the trip solenoids I82, I83, I04, I88.

'of well known ways and for the purpose of this specification a conventional audio-frequency A. C. amplifier with a self-contained source of B supply is preferably used and is enclosed in a casing indicated by the numeral I65 in Fig. 9.

.Such an amplifying step is well known in the art and therefore it is thought unnecessary to further describe and explain it.

The amplified A. C. electric output of the bridge circuit for a given sheet A is utilized to energize the proper trip solenoid I02, I83,-I84, I05 and thereby discharge the gauged sheet at the proper station. However, since the machineishown in the drawings is arranged to sort the sheets A into four distinct classifications, there will be four different outputs of the bridge circuit and therefore the proper output must be selected to operate the proper solenoid. This is preferably efiected by a selector system of electric circuits shown at the right in Fig. 9 and which perform their functions through a plurality of thyratron tubes and relays as will now be explained.

- There are preferably four thyratron tubes, numbered I12, I13, I14 and I15 (Fig. 9) one for each of the respective sorting stations L, M, N, 0. Each tube is formed with a heating filament or cathode I16, a grid I11, and an anode I18.

The cathodes I16 of all the tubes are connected by way of wires I8I, I82 to a secondary winding TIS of a transformer TI. The primary winding TIP of this transformer is connected by lead wires I83, I84 to a suitable source of alternating current.

All the thyratron tubes are negatively biased by a source of "3 supply to create a D. C. potential. For this purpose there is provided a stepup transformer T2 and a full wave rectifier tube I86 which is connected into a filter circuit generaliy indicated by the numeral I81. The primary winding 'I,2P of the transformer T2 is preferably connected into the lead wires I83, I84 of the main source of alternating current. The secondary winding T28 of the transformer T2 is connected by wires I88, I89 to the rectifier tube I88 The filter circuit I81 also includes a plurality of cross. wires I9I, I92, I93 connecting coupling condensers I94, I95, I96 to a main lead wire I91 which connects with the secondary winding T28 and to a main lead wire I98 which connects with the filament of the rectifier tube I86. At one side us, one for each thyratron tube n2, n3, n4, 8 n5.

The movable arms of the potentiometers 2I5, 2I6, 2I1, 2I8 are connected first through resistors 220 to respective wires 22I, 222, 223, 224 each wire of which leads through a condenser 228 to a lead wire 226 which is. connected into the A. C. amplifying circuits in the housing I65 and which receives the amplified output of the bridge circuit hereinbefore mentioned. The amplifying circuits are also connected .by a lead wire 221 to the voltage divider system wire 2| I.

The grid I11 of'each thyratron tube I12, I13, I14, "-5 is connected by respective wires 232, 233, 234, 235 and resistors 231, 238, 239, 240 to the respective potentiometer wires 22I, 222, 223, 224 at places between the condensers 228 and resistors-229 in these wires.

The anode I18 of each thyratron tube I12, I13, I14, I 15, is connected by respective wires 245, 246, 241, 248, to coils of respective relays 25I, 252, 253, 254. These relays are connected into a main lead wire 255 which connects with the lead wire I98 of the B supply of current.

The cathodes of the thyratron tubes I12, I13,

"114,115 are connected by a. wire 251 to the voltage divider' system wire 2 at a reference point X.

Thus it will be readily seen from the wiring diagram that a thyratron tubewill be biased negatively by means of the voltage existing between the reference point X in the voltage divider system and the setting on the potentiometer associated with that tube. For example, thyratron tube I12 will be biased by means of the voltage existing between point X and the arm of the potentiometer 2I5. In the same manner tubes I13, I14, I15 are biased by the voltages existing between point X and the respective arms of potentiometers 2I8, 2I1, 2I8. It is therefore evident that tube I12 has theiminimu'm bias and tube I15 has the maximum bias.

A relay 25I, 252, 253, 254 in the anode circuits of the thyratron tubes can become energized on y if that tube conducts. When no sheets A pass between the gauging rollers 32, 33 of the gauging device C the amplified electric output of the bridge circuit is the minimum output voltage and is not of sufiicient magnitude to cause even the minimum biased tube I12 to become conducting. Therefore none of the tubes conduct when no sheets pass between the gauging rollers.

However, a thyratron tube can be made to conduct through the setting of its associated one-thousandths of an inch through the gauging device. Similarly potentiometer 2 I 6 is set to permit tube I13 to conduct when the output of the bridge circuit is further increased by a sheet of nine one-thousandths of an inch thick. In like manner potentiometers 2", 2| 8 are set to permit tubes I14, I15 to conduct for sheets of ten and eleven one-thousandths of an inch thick.

When a thyratron tube conducts it energizes its associated relay. Thus when tube I12 conducts, relay 25I will be energized. In like manner when tubes I13, I14, I15 conduct the respective relays 252, 253, 254 will be energized. I

The maximum amplified voltage of the bridge circuit which is of sufllcient magnitude to cause tube I15 to conduct will also cause the other tubes to conduct and thereby cause all the relays to be energized at once. To prevent the undesired relays from remaining energized provision is made for locking out all the relays excepting that selected one which should be responsive to the particular thickness of the sheet being gauged. This is eiIected by a set of normally closed contacts 26I, 282, 263 which are connected into the tube anode circuit lead wire 255. These contacts are opened by the respective relays 252, 253, 254 when they are energized.

Since the voltage necessary to cause thyratron tube I12 to conduct is the minimum increased output of the bridge circuit, this tube when conducting will only energize relay 25I and not the others therefore no contacts are necessary for this relay. However, when relay 252 is energized it opens its contacts 26I and thereby breaks the tube anode circuit leading to relay 25I. This locks out the relay 25I. When relay 253 is energized it opens its contacts 262 and thereby looks out relays 25I, 252 and when relay 254 is energized it opens its contacts 263 and thus locks out all the others. 9

When a thyratron tube is operated with D. C. on its plate, it will continue to conduct, after being rendered conducting, until the flow of current is interrupted externally by means of a switch in the anode circuit. For this purpose there is provided a timing switch 266 which is connected into the anode circuit lead wire 255. The 'switch is opened and closed by a cam 261 which may be actuated in any suitable manner in time with the other moving parts of the machine.

The function of the timing switch 266 is to break theanode circuit of all the thyratron tubes I12, I13, I14, I15 once for each sheet passing between the gauging rollers 32, 33 of the gauging device C. The cam 261 operates to close the switch when the gauging rollers are at a certain point on the sheet being gauged and to open the switch after the sheet has traveled a predetermined distance between the rollers. this manner the actual gauging of the sheet is confined to as small a distance as is found necessary in order to minimize the effect of the drip edge and too great a variation in the thickness over the entire sheet.

Energizing of the relays 25I, 252, 253, 254 closes a set of solenoid circuits which are associated with the trip solenoids I02, I03, I04, I which segregate or sort the gauged sheets A into piles of like thickness as hereinbefore mentioned. These circuits receive electric energy from a suitable source such as a generator 21I. One side of the generator is connected by a lead wire 212 to each of the trip solenoids, and to the ground.

The opposite side of the generator is connected by a lead wire 213 to a normally open switch 214 which is operated by relay 254. 'l'he switch is also connected by a wire 215 to the solenoid I05. One side of the open switch 214 is connected by a wire 211 to a normally closed switch 218 which is also operated by relay 254.

5 Switch 218 is connected by a wire 219 to a normally open switch 280 which is operated by rela'y 253. The latter switch 280 is connected by a wire 28I to the trip solenoid I04.

In this same stepped manner the normally open switch 280 is connected by a wire 283 to a normally closed switch 284 which is operated by relay 253. This closed switch 284 is connected by a wire 285 to a normally open switch 286 which is operated by relay 252. Switch 286 is connected by a wire 281 to the trip solenoid I03. The normally open switch 286 is connected by a wire 288 to a normally closed switch 289 which is operated by relay 252. Switch 289 is connected by a wire 29I to a normally open switch 292 which is operated by relay 25I and switch 292 ilsnzconnected by a wire 293 to the trip solenoid This system of interlocking normally open and normally closed switches provides for locking out all trip solenoids excepting that one which should be energized for a sheet A of given thickness when it is being gauged. Thus when no sheet is being gauged and therefore none of the relays are energized, the normally open solenoid switches 214, 280, 286, 282 maintain the solenoid circuits broken and thereby maintain the trip solenoids I02, I03, I04, I05 in a deenergized condition. However, when a sheet of eight one-thousandths thickness is being gauged, relay 25I is energized and this closes the normally open switch 292. Hence the solenoid circuit through trip solenoid I02 (as traced on the drawings) is closed and electric energy from generator 21I will energize It.

When a sheet of nine one-thousands of an inch thickness is being gauged, relay 252 is energized. Energizing of this relay closes the normally open switch 286 and thereby permits the trip solenoid I03 to become energized but the relay simultaneously opens the normally closed switch 289 and thereby locks out the circuit containing the trip solenoid I02. Hence even though switch 292 should he accidentally closed the circult containing trip solenoid I02 will remain open and therefore solenoid I02 could not be energized.

In like manner the energizing of relays 253, 254 for sheets of ten and eleven one-thousandths of an inch thick will close only the circuit containing its particular solenoid I04 or I05 and lock out all the other circuits to insure that only the desired trip solenoid will be energized and thus insure that the sheet A as gauged by the gauging device C will be placed in the proper hand truck H as hereinbefore explained.

This sheet thickness sorting circuit as shown in Fig. 9 is very flexible and can be extended to sort sheets or any other type of article into any number' of classifications by the addition of thyratron tubes, relays and bias potentiometers. The settings on the potentiometers determine the increments in the degree of classification and there is thereby furnished an easy and quickly changeable way of sorting articles into any dimenslonal classification desired.

It is thought that the invention and many or its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

We claim:

1. In a machine for sorting sheets of magnetic material in accordance with their thickness, the combination of a belt conveyor for conveying the sheets in a continuous procession along a predetermined path of travel through a plurality of sheet sorting stations, normally energized electro-magnets at said sorting stations for retaining the sheets on said conveyor and when de-energized for releasing the sheets into piles of like thickness, a normally de-energized stripper element at each sorting station, an electric gauging device for gauging the thickness of the sheets, said gauging device having an electric output which varies with the thickness of the sheets being gauged, and electric instrumentalities responsive to the electric output of said gauging device for de-energizing said electro-magnets and for energizing said stripper element at the proper sorting station for discharging the sheets from the conveyor.

2. In a machine for sorting sheets in accordance with their thickness, the combination of an electric gauging device for gauging the thickness of sheets, said gauging device having an electric output which varies with the thickness of the sheet being gauged, means for amplifying the electric output of said gauging device, sorting elements for sorting the sheets into respective classifications, a thyratron tube for a class desired, a voltage divider circuit including a potentiometer connecting with the grid circuit of each tube, said grid circuit being responsive to the electric output of said gauging device, said potentiometers having progressive potential differences to negatively bias said tubes so that one tube will conduct on a minimum output of said gauging device, another tube on a maximum output of said gauging device, and the intermediate tubes on outputs progressing from minimum to maximum output, devices in the anode circuits of said tubes for locking out all of the tubes of lower negative bias than the selected tube which is responsive to a predetermined electric output of said gauging device when gauging a sheet of predetermined thickness, and a relay also in the anode circuit of each tube and energized by the conduction of its tube for actuating a predetermined sorting element.

3. In a machine for sorting sheets in accordance with their thickness, the combination of an electric gauging device having an electric output comprising a variable alternating voltage the magnitude of which varies with the thickness of the sheet being gauged, electric instrumentalities including a plurality of thyratron tubes to the grids of which the said voltage output of said gauging device is applied, and sorting elements connected with said thyratron tubes for sorting the sheets into respective thickness classifications, the thyratron tube selectively responding to the magnitude of the electric output imposed on its grid becoming conducting and actuating its corresponding sorting element for sorting a gauged sheet according to thickness.

4. In a machine for sorting sheets in accordance tron tube so as to render the same selectively responsive to a grid voltage input correspondin to the thickness classification of the sheet being gauged, and sorting elements connected with said thyratron tubes for sorting the sheets into respective thickness classifications.

5. In a machine for sorting sheets in accordance with their thickness, the combination of an electric gauging device having an electric output comprising a variable alternating voltage the magnitude of which varies with the thickness of the sheet being gauged, electric instrumentalities including a plurality of thyratron tubes to the grids of which the said voltage output of said gauging device is applied, means for adjusting the bias on each thyratron tube so that one tube will conduct on a minimum output of said gauging device and another tube on a maximum output of said gauging device, and sorting elements connected with said thyratron tubes for sorting the sheets into respective thicknesss classifications.

6. A machine for sorting sheets in accordance with their thickness, comprising an electric gauging device having an electric output which varies with the thickn ss of the sheet being gauged, sorting elements or sorting the sheets into respective classificatons, a thyratron tube for a class desired, means for adjusting the bias on each thyratron tube so th'at one tube will conduct on a minimum output of said gauging device, another tube on a maximum output of said gauging device, and the'intermediate tubes on outputs progressively from minimum to maximum output, and a relay associated with each tube and energized by the conduction of its tube for actuating a predetermined sorting element.

7. In a machine for sorting sheets of magnetic material in accordance with their thickness, the combination of means for conveying the sheets in a continuous procession along a predetermined path of travel through a plurality of sheet sorting stations, normally energized electro-magnets at said sorting stations for retaining the sheets on said conveyor and when de-energized for releasing the sheets into piles of like thickness, a normally de-energized stripper element at each sorting station, an electric gauging device for gauging the thickness of the sheets, said gauging device having an electric output which varies with the thickness of the sheets being gauged, and electric instrumentalities responsive to the electric output of said gauging device for de-energizing said electro-magnets and for energizing said stripper element at the proper sorting station for discharging the sheets from the conveyor.

HAROLD T. ODQUIST. BENJAIVIIN SHMURAK.

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