US2693885A

US2693885A - Control circuit for sheet feeding and stacking apparatus

Info

Publication number: US2693885A
Application number: US250277A
Authority: US
Inventors: Junco Louis
Original assignee: Universal Corrugated Box Mach
Current assignee: Universal Corrugated Box Machinery Corp
Priority date: 1951-10-08
Filing date: 1951-10-08
Publication date: 1954-11-09
Anticipated expiration: 1971-11-09

Description

L. JUNCO Nov. 9, 1954 CONTROL CIRCUIT FOR SHEET FEEDING AND STACKING APPARATUS 2 Shets-Sheet 1 Filed Oct. 8, 1951 I INVENTOR Louis Janco A, I oflealw mw w ATTORNEYS L. JUNCO 2,693,885 CONTROL CIRCUIT FOR SHEET FEEDING AND STACKINGY APPARATUS Nov. 9, 1954 2 Sheets-Sheet 2 Filed Oct. 8, 1951 S wmm 1 M ATTORNEYS INVENT O Louis Jun/c0 BY 4% vs m R \w ma NQ nited States Patent CGNTROL CIRCUIT FOR SHEET FEEDING AND STACKING APPARATUS Louis Junco, New York, N. Y., assignor to Universal Corrugated Box Machinery Corporation, a corporation of New York Application October 8, 1951, Serial No. 250,277

18 Claims. (Cl. 214-6) This invention relates to a control circuit, more particularly for sheet feeding and stacking apparatus.

The control circuit hereinafter to be described is especially designed for use with apparatus of the type shown and described in Patent No. 2,506,550, dated May 2, 1950, and is designed to replace the control equipment shown and described in such patent.

As conducive to an understanding of the invention, it is noted that where sheets of corrugated board, for example, are successively discharged onto a conveyer for stacking, and a micro-switch is mechanically operated by the topmost sheet of the stack to stop further delivery of such sheets when the stack has reached a predetermined height due to the impact of the sheet against the micro-switch, the latter is likely to break down with resultant need for servicing and repair and consequent stoppage of the feeding and stacking apparatus, as well as the apparatus for forming the sheets which generally is in an assembly line with the sheet feeding and stacking apparatus, and which is designed to operate continuously. As a result, continuous operation of the apparatus will be impossible with resultant reduction of the maximum possible output.

in addition, where it is desired to change the number of sheets to be stacked in a single pile, the apparatus must be stopped for regulation of the height of the microswitch, which adjustment in addition to being time consuming, also will reduce the output.

Where, after a predetermined number of sheets has been stacked on such conveyor and the latter is advanced to move the stack away from the original stacking position, a photoelectric cell is used to control resumption of discharge of the sheets onto the conveyer. for stacking, due to the sensitivity of the photoelectric cell, the latter is likely to break down as a result of the vibration of the apparatus caused by the discharge of sheets thereon. In addition, as the apparatus is generally installed in factories where dirt and dust is likely to accumulate, the surface of the photoelectric cell may become obscured with frequent need for cleaning thereof, which also requires stoppage of the equipment.

As the photoelectric cell must be set in a fixed position for use, where sheets are to be stacked that are of different width than those in previous pile, for efiicient operation of the apparatus, the position of the photoelectric cell would have to be adjustable. Such adjustment is required inasmuch as if the subsequent sheets are wider than those on the pile previously formed more time would be required for the stack to be transported away from the stacking position than if they were narrow. This adjustment of the location of the photoelectric cell is clumsy and time consuming and the continuous operation desired for maximum output would be impossible to achieve.

In addition, where photoelectric cells are used, if an outside source of light, such as a ray of sun, should strike the photoelectric cell, the latter would cause resumption of the discharge of sheets to form the next stack before the stack previously assembled had been transported away from the stacking position with resultant malfunctioning of the apparatus.

It is accordingly among the objects of the invention to provide acontrol circuit for a sheet feeding and stacking apparatus of the above type whichdoes not require micro-switches or photoelectric cells for operation thereof and which may readily be setby an operator Free without need for stoppage of the apparatus automatically to determine the number of sheets to be stacked and to handle sheets of any desired width, which control equipment is relatively simple and not likely to become de= ranged even with long use, and which may readily be switched for manual operation also without need for stoppage of the equipment.

According to one aspect of the invention, the automatic portion of the control circuit includes a plurality of vacuum tubes each having an adjustable timing circuit associated therewith which operate relays in predetermined sequence to permit discharge of a pre-selected number of sheets onto a conveyer and after said pre-selected num-- ber of sheets have been stacked, stops further delivery of sheets to such conveyer and after a suitable time interval, advances the conveyer for transportation of such stack away from the stacking position. The control circuit also is designed to effect resumption of discharge of sheets for stacking onto the conveyer after a predetermined time has elapsed which may be set at any desired value, depending upon the width of the sheets in the stack so that the stack may be moved away from the stacking position prior to resumption of the discharge of sheets onto the conveyor. The circuit also includes a manual control which may readily be switched into operation and which, when actuated, will first permit discharge of sheets onto the conveyer for stacking and thereafter, at the control of the operator after any desired number of sheets has been stacked, stops further delivery of sheets, The circuit may then be operated to transport the stack away from the stacking position and to effect resumption of discharge of the sheets for stacking' of another pile.

in the accompanying drawings in which is shown one of various possible embodiments of the several features of the invention,

Fig. 1 is a perspective view of the sheet feeding and stacking apparatus, and

Fig. 2 is a diagrammatic view of the control circuit.

Referring to the drawings, the apparatus comprises a feed conveyer 11 which may be continuously driven by means of a motor 12, and a discharge conveyer 13, preferably disposed at right angles to conveyer 11 and desirably intermittently driven by means of a motor 14. The conveyer 11 is desirably associated with a sheetforming machine (not shown) which includes a pair of feed rollers 15 to discharge the sheets to be stacked, such as corrugated sheets 16, onto the conveyer 11 which will feed such sheets to conveyer 13 for stacking thereon, Desirably the conveyer 11 is driven at a slower speed than the feed rollers 15 so that the sheets 16 will be in overlapping relation as shown, on conveyer 11.

The conveyer 11 may comprise a pair of endless belts 17 and 18, the belt 17 passing around driving roller 19 and idler roller 21 and having its upper run supported by a plate 22, and the belt 18 passing around driving roller 23 and an idler roller 24. The sheets 16 are fed by the feed rollers 15 into position between the belts 17 and 18 which will carry them, during the stacking periods, onto the conveyer 13;

In order to control feed of the sheets 16 from the discharge end 20 of belts 17 and 18 through drive feed rollers 27 onto conveyer 13, a gate assembly 25 is providedv As shown in Fig. 1, the gate assembly 25 desirably comprises an angle bar or gate 26 suspended transversely of the conveyer 11 just ahead of the roller 24. Gate 26 may be suspended by thearmatures 28 of a pair of solenoids 29 of any suitable type which may be mounted on theframe 30 of the machine and is normally in raised posltlon when the solenoids 29 are not energized. The gate 26 may be lowered to move its flange 31 across the discharge end 20 of the conveyers 17, 18 and into contact with a transverse I beam 32 of the frame to interrupt delivery of the sheets 16 from between the conveyer belts 17 and 18 onto discharge conveyer 13. The

against which the sheets 16 may abut for stacking and suchstop member is adjustable to accommodate sheets of any desired widt The equipment above described is designed to operate in a sequence of steps so that the sheets'will firstbe ad vanced by the continuously driven conveyer 11 through the normally raised gate 26 and the rollers 27 and successively discharged onto the conveyer 13 to stack up against the stop 33. After a predetermined number of sheets has been stacked, the gate 26 is lowered to stop further discharge of sheets and the conveyer 13 is advanced to move such stack laterally to a delivery station. Inasmuch as a sheet may be passing beneath the gate when it is lowered, a slight time delay is required before the discharge conveyor 13 is advanced, to permit such last sheet to be stacked. After the stack of sheets has been moved laterally past the gate 26, the discharge conveyer 13 is stopped and the gate 26 is raised to repeat the cycle.

According to the invention, to control the sequence of operation of the equipment, the circuit shown in Fig. 2 is provided.

The drive motor 14 for conveyer 13 is desirably connected by

leads

81, 82 and 83 to the

movable switch arms

84, 85 and 86 respectively, of a motor switching relay 87. The fixed contacts 88, 89 and 91 of said relay 87 are connected by

leads

92, 93 and 94, to a main power switch 95 which is connected to a suitable source of potential 96.

Leads 93 and 94 are connected by leads 97 and 98, respectively, to the primary winding 99 of a transformer 101, desirably of the stepdown type, so that if 240 volts for example, is connected to primary 99, the voltage across the secondary winding 102 will be 120 volts.

One side of secondary winding 102 is connected by lead 103 to terminal 104 of automatic control unit 105, said terminal being connected by lead 106 to one side of the parallel connected filaments 107 of

vacuum tubes

108, 109 and 111 in control unit 105. The other side of said filaments is connected by lead 112 to terminal 113 of control unit 105 and from said terminal 113 by lead 114 to the other side of secondary winding 102. Desirably a fuse 115 is connected in lead 114 to protect transformer 101 in case of sudden current surges in the line as for example, caused by a short circuit.

The secondary winding 102 is also connected through lead 117 to the movable switch arm 118 of a single pole double throw selector switch 119, actuation of which determines whether the device is on automatic or manual operation. Fixed contact 121 of switch 119, which is illustratively shown engaged by movable arm 118, is connected by lead 122 to terminal 123 of automatic control unit 105 and said terminal 123 is connected by lead 124 to one side of a potentiometer 125, illustratively of 10,000 ohms, connected in series with a resistance 126, illustratively of 10,000 ohms which is connected by leads 127 and 112 to terminal 113. Potentiometer 125 and resistor 126, which form a voltage divider, are thus connected across the secondary 102 of transformer 101 when switch 119 is in automatic position as shown, and a pilot light 128 is desirably connected in parallel with potentiometer 125 and resistor 126 to indicate when current is flowing therethrough.

Associated with potentiometer 125 and resistance 126 is the vacuum tube 108 which desirably has a triode section comprising a plate 131, a grid 132 and a cathode 133 and a diode section comprising a plate 134 and a cathode 135, all contained in a common envelope.

The grid 132 is connected by lead 136 to one side of a capacitor 137, desirably of 8 mid, the other side of which is connected by lead 138 to the movable arm 139 of potentiometer 125, a resistance 141 desirably of 1 megohm being connected across capacitor 137 to provide a discharge path therefor.

The plate 131 is connected by lead 142 to one side of coil 143 of relay 144 which is connected in series with the coil 145 of relay 146. Coil 145 is connected by leads 147 and 148 to plate 149 of the diode section of tube 111, by lead 151 to one side of resistance 152, desirably of 10,000 ohms, and by lead 153 to one side of resistance 154 also desirably of 10,000 ohms, the other side of which is connected by lead 155 to cathode 133 of tube 108. Desirably a capacitor 156, preferably of 8 mid. is connected across coils 143 and 145 to provide a substantially continuous flow of current therethrough during the positive and negative halves of the alternating current cycle.

The cathode 135 of the diode section of tube 108 is connected by

leads

157, 158 and 159 to the movable contact arm 161 of relay 144, which is normally engaging fixed contact 162 when said relay 144 is deenergized. Cathode 135 is also connected by lead 163 to one side of capacitor 164, desirably of 16 mfd., the other side of which is connected by

leads

165 and 166 to lead 124 as at 167. Lead 165 is connected by lead 168 to junction 255 which is connected by leads 169 and 171 to the movable arm 172 of relay 146 which is normally spaced from fixed contact 173 when relay 146 is deenergized. Lead 165 is also connected by

leads

168, 169 and 174 to one side of the coil 175 of relay 176, the other side of said coil being connected by lead 177 to fixed contact 162 of relay 144.

Relay 176 has a movable contact arm 178 normally spaced from

fixed contacts

179 and 181 when relay 176 is deenergized. Fixed contact 181 is connected by lead 182 to terminal 183 of the automatic control unit 105 and terminal 183 is connected by leads 184 and 185 to one side of the solenoids 29 which control the gate 26, the other side of said solenoids being connected by lead 186 to lead 93.

Fixed contact 179 of relay 176 is connected by lead 187 to terminal 188 of the automatic control unit 105 and said terminal 188 is connected by

leads

191 and 192 to fixed contact 193 of hand control motor switch 194, and by lead 195 to lead 92. The movable arm 196 of switch 194 is connected by

leads

197 and 198 to one side of the coil 199 of motor relay 87', the other side of which is connected by lead 201 to fixed contact 89 of said relay.

The movable arm 196 of switch 194 is also connected by lead 203 to terminal 204 of automatic control unit 105 and from terminal 204 by lead 205 to fixed contact 206 of relay 207. Associated with fixed contact 206 is a second fixed contact 208 which is connected by lead 209 to lead 187. Contacts 206 and 208 have a contact arm 211 associated therewith and normally spaced therefrom when the coil 212 controlling switch arm 211 is deenergized.

One end of coil 212 is connected by lead 213 to lead 174 and the other end of said coil 212 is connected by lead 214 to fixed contact 215 of relay 216. The movable contact arm 217 of relay 216 which is normally spaced from fixed contact 215 when the coil 218 of relay 216 is de energized, is connected by

leads

219 and 221 to the cathode 222 of the diode section of vacuum tube 109 and also by

leads

219 and 223 to the junction 224 between

leads

158 and 159.

The coil 218 of relay 216 is connected in series with the coil 225 of a relay 226. Coil 218 is connected by lead 227 to the plate 228 of vacuum tube 109 and coil 225 is connected by leads 229 and 231 to one end of resistor 232, desirably of 10,000 ohms. The other end of resistor 232 is connected by

leads

233 and 234 to the cathode 235 of tube 109 and by

leads

233 and 230 to fixed contact 173 of relay 146. Desirably a capacitor 236, preferably of 8 mfd. is connected across the coils of

relays

216 and 226 to provide a constant flow of current through said coils during the positive and negative halves of the alternating current cycle.

The grid 241 of tube 109 is connected by lead 242 to one side of a capacitor 243, desirably of 8 mid, the other side of which is connected to the movable arm 244 of a potentiometer 245. As shown, a resistor 246, desirably of 2 megohms, is connected across capacitor 243 to provide a discharge path therefor. Potentiometer 245 is connected in series with resistor 152 to form a voltage divider. Resistor 152 is connected by

leads

247 and 248 to the plate 249 of the diode section of tube 109 and by

leads

247 and 251 to the junction 252 between lead 229 and 231. Potentiometer 245 is connected by

leads

253 and 254 to the junction 255 between

leads

168 and 169 and by

leads

253, 256, 257 and 258 to the movable contact arms 259 and 261 of relays 226 and 263.

Movable arm 259 of relay 226 is normally spaced from fixed contact 264 when the coil 225 of relay 226 is deenergized, and said fixed contact 264 is connected by

leads

265 and 266 to the cathode 267 of tube 111.

Movable arm 261 of relay 263 normally engages fixed contact 268 when coil 269 of said relay is deenergized, and contact 268 is connected by lead 271 to lead 155. One end of the coil 269 of relay 263 is connected by lead 272 to the plate 273 of tube 111 and the other end of coil 269 is connected by leads 274 and 148 to the plate 149 of the diode section of tube 111 and by

leads

274 and 275 to one end of resistor 276, desirably of 10,000 ohms, the other end of which is connected to lead 266. As shown, coil 269 has a capacitor 277, desirably of 8 mid, connected thereacross to provide a constant tlow of current during the positive and negative halves of the alternating current cycles.

The grid 281 of tube 111 is connected by lead 282 to one side of a capacitor 283, desirably of 8 mid, the other side of which is connected by lead 284 to the movable arm 285 of a potentiometer 286, desirably of 10,000 ohms. As shown, a resistance 287, desirably of .15 megohm, is connected across capacitor 283 to provide a discharge path therefor.

Potentiometer 286 is connected in series with a resistor 288 also desirably of 10,000 ohms, to form a voltage divider. Resistor 288 is connected to lead 147 as at 290, and through lead 148 to plate 149 of tube 111, and the potentiometer 286 is connected by lead 293 to the junction 255. The cathode 294 of the diode section of tube 111 is connected by lead 295 to the junction 296 between

leads

157 and 158 to complete the circuit of the automatic control unit 105.

The manual control unit 301 desirably comprises a rectifier 302 which may be of any suitable type and is illustratively shown as a selenium rectifier designed to give a direct current output of say 120 volts. The input terminals 303 and 304 of the rectifier 302 are connected by

leads

305 and 306 respectively, to

terminals

307 and 308 of manual control unit 301 and have a pilot light 309 connected thereacross to indicate when current is flowing to the rectifier 302. Terminal 307 is connected by lead 310 to lead 114 and terminal 308 is connected by lead 311 to fixed contact 312 of selector switch 119.

One of the output terminals 313 of rectifier 302 is connected by common lead 314 to one side of the

coils

315, 316, 317, 318, 319, 321 and 322 of

relays

323, 324, 325, 326, 327, 328 and 329. The other output terminal 331 of rectifier 302 is connected by lead 332 to one side of capacitor 333, desirably of 16 mfd., the other side of which is connected by

leads

334 and 335 to common lead 314. Capacitor 333 is also connected by leads 334 and 336 to one side of capacitor 337 desirably of 8 mfd., the other side of which is connected by lead 338 to the movable switch arm 339 of manual switch 341, desirably of the foot operated type. As shown, capacitor 337 has a resistor 342, desirably of 5,000 ohms, connected thereacross.

Output terminal 331 is also connected by lead 344 to fixed contact 345 of switch 341 which is illustratively shown engaged by contact arm 339 and by leads 344 and 346 to movable contact arm 347 of relay 329. Arm 347 normally engages fixed contact 348 when coil 322 is not energized and said fixed contact 348 is connected by common lead 349 to

movable contact arms

351, 352, 353 and 354 of

relays

327, 328, 325 and 326.

The free end of coil 319 of relay 327 is connected by lead 356 to fixed contact 357 of relay 358, the movable arm 359 of which is normally spaced from contact 361 when the coil 362 of relay 358 is not energized, said contact 361 being connected by lead 360 to coil 322 of relay 329. Arm 359 normally engages fixed contact 357 connected to one end of said coil 362 and the latter is connected by lead 363 to fixed contact 364 of relay 327.

Movable arm 359 of relay 358 is connected by lead 366 to the fixed contact 367 of relay 368, the movable arm 369 of which is normally spaced from said contact 367 and engages fixed contact 371 when coil 372 of relay 368 is not energized. Fixed contact 371 is connected to one end of coil 372 and by lead 374 to one end of coil 318 of relay 326. The other end of coil 372 of relay 368 is connected by lead 375 to fixed contact 376 of relay 326. Movable arm 369 of relal 368 is connected by lead 377 to one side of rectifier 378, the other side of which is connected by lead 3'79 to fixed contact 381 of switch 341.

The fixed

contacts

382 and 383 of

relays

326 and 327 which are normally engaged by the associated

movable arms

354 and 351 when the relays are not energized, are connected through resistors 384 and 385 respectively, each desirably of 5,000 ohms, to one side of the

coils

317 and 321 of

relays

325 and 328.

The fixed contact 386 of relal 325 which is normally engaged by movable switch arm 353 when coil 317 is not energized, is connected by lead 387 to one end of coil 315 of relay 323. The fixed contact 388 of relay 328 which is normally spaced from movable arm 352 when coil 321 is not energized, is connected by lead 389 to one side of the coil 316 of relay 324.

The movable arm 391 of relay 323 which normally is connected by lead 393 to terminal 394 of the manual control unit 301 and such terminal 394 is connected by v lead 395 to lead 185. Fixed contact 392 is connected by lead 396 to terminal 397 and the latter is connected by lead 398 to lead 191. Contact 392 is also connected by lead 399 to movable arm 401 of relay 324 which is normally spaced from fixed contact 402 when said coil 316 is not energized, and fixed contact 402 is connected to terminal 403 which is connected by lead 404 to lead 203.

Operation The operation of the control equipment will be described, assuming that such equipment is in the middle of a cycle, feeding sheets onto discharge conveyer 13 and which selector switch 119 set for automatic operation and with

capacitors

137, 164, 243 and 283 charged. As a result, the bias on

tubes

108, 109 and 111 will be such as to cut off said tubes so that they will be nonconducting.

Due to the resistor 141 in parallel with capacitor 137, the latter will discharge through said resistor, the length of time of such discharge depending upon the time constant of the resistor 141 and capacitor 137 and the setting of potentiometer which determines the amount of charge of capacitor 137. The values are so selected that this time may be set from one to 30 seconds, depending upon the number of sheets it is desired to stack on the discharge conveyer 13.

After sufiicient period of time has elapsed so that the charge on capacitor 137 has fallen below the cutofi point of tube 108, the latter will be in condition to conduct. As the 120 volt alternating current output of transformer 101 is connected across the plate 131 and cathode 133 of tube 108, during the positive half of the cycle, current will flow through such tube and the coils of relays 144 and 146, to open the contacts 161, 162 of relay 144, and to close the

contacts

172, 173 of relay 146.

The circuit is from terminal 113, to which one side of transformer secondary 102 is connected by lead 114; leads 112 and 127 through the series connected coils 145 and 143 and lead 142 to plate 131, and from terminal 123 to which the other side of transformer secondary 102 is connected by lead 117, switch 119 and lead 122;

,leads 166, 168, junction 255, leads 254, 256 and 258,

relay 176. This circuit is from one side of capacitor 164,

leads 163, 157, 158, 159, contacts 161, 162, lead 177, coil 175, leads 174, 169, junction 255, leads 168, to the other side of capacitor 164. As a result, coil will be deenergized and the switch arm 178 of relay .17 6 will move away from fixed

contacts

179 and 181. This will break the circuit to solenoids 29 which control the gate 26 and the latter will fall, blocking the further passage of sheets 16 through rollers 27. In the event that a sheet 16 should be between the gate 26 and bar 32 when the gate is released, the gate will rest on such sheet and the rollers 27 will draw such sheet from beneath the gate and deposit it on the stack on the discharge conveyer 13. Thereafter, as long as the gate 26 is closed, no further sheets can pass therethrough.

As the

contacts

172 and 173 of relay 146 will close simultaneously with the opening of contacts 161 and 162 of relay 144, the cathode 235 of tube 109 will be connected to terminal 123, the circuit being from cathode 235, leads 234 and 230,

closed contacts

172 and 173, lead 171, 169, 168 and 166. As the plate 228 of tube 109 is connected to terminal 113 through lead 227, the

coils

218 and 225 of

relays

216 and 226, leads 229, 251, 247, 151, 127 and 112, a potential of 120 volts from the transformer secondary 102 will be connected across the plate and cathode of said tube 109.

However, as capacitor 243 is charged sufficiently to retain tube 109 cut off, the latter will not conduct until suflicient time has elapsed for capacitor 243 to discharge through resistor 246 to a value below the cut ofi voltage required. The time delay is set by adjusting potentiometer 245 so that only after sufiicient time has elapsed after the gate has closed for the last sheet to pass therethrough, will the charge on capacitor 243 fall enough to permit tube 109 to conduct.

At this time current will flow through the

coils

218 and 225 of relays 216 and'226 to close the

open conaesasss tacts

215, 217 and 264, 259 of said relays respectively. Closing of

contacts

215, 217 of relay 216 will complete a circuit from one side of capacitor 164 (which charges due to the flow of current through the

plates

134, 249, 149 and

cathodes

135, 222, 294 of the diode sections of

tube

108, 109 and 111 which are connected across terminals 113 and 123 connected to transformer secondary 102), leads 163, 157, 158, 223, 219,

closed contacts

215, 217, lead 214, coil 212 of relay 207, leads 213, 174, 169, 168 and 165 to the other side of capacitor 164. As a result, current will flow through coil 212 of relay 207 to move switch arm 211 to bridge fixed contacts 206 and 208 thereby to complete a circuit to the coil 199 of the motor switch relay 87.

The circuit is from main 92, leads 195, 192, 191 to terminal 188, leads 187, 209 to bridged contacts 206, 208, lead 205 to terminal 204, leads 203 and 198 to coil 199 and thence to fixed contact 89 and main 93. As a result 240 volts will be applied to coil 199 to energize the latter and close the circuit to conveyer motor 14 to advance conveyer 13 to move the stack of sheets thereon away from the gate 26.

Simultaneously with the closing of

contacts

215 and 217 of relay 216, contacts 259 and 264 of relay 226 will close to connect terminal 123 to the cathode 267 of tube 111. The circuit is from such terminal 123, leads 166, 168, 254, 256, 257, contacts 259, 264 of relay 226, leads 265 and 266 to cathode 267. As the plate 273 of tube 111 is connected to terminal 113 through lead 272, coil 269 of relay 263, leads 274, 147, 127 and 112, 120 volts alternating current will be applied from transformer secondary 102 across tube 111.

As the capacitor 283 is charged sufficiently to retain tube 111 cut 011, it will not conduct until sufficient time has elapsed for capacitor 283 to discharge through resistor 287 to below the cut off point of tube 111. The time delay is set by adjusting potentiometer 286 so that only after suflicient time has elapsed to permit motor 14 to advance discharge conveyer 13 to move the stack of sheets thereon past the gate 26 will tube 111 conduct.

Conduction of tube 111 will cause current to flow through the coil 269 of relay 263 to open the

contacts

261, 268 thereof. As a result terminal 123 will be disconnected from the cathode 133 of tube 108 and terminal 113 will be connected through resistor 154 to said cathode 133, the circuit being from terminal 113, leads 112, 127, 153, resistor 154 and lead 155 to said cathode.

As the plate 131 of tube 108 is normally connected to terminal 113, the cathode 133 and plate 131 will now be at the same polarity, so that the current flow through tube 108 will immediately cease, thereby deenergizing the coils 143 and 145 of relays 144 and 146. Simultaneously the grid 132 of tube 108, during the positive half of the alternating cycle, will be positive with respect to the cathode 133 so that current will flow from terminal 113, leads 112, 127, 153, resistor 154, lead 155, cathode 133 through grid 132, parallel connected capacitor 137 and resistor 141, lead 138, arm 139, potentiometer 125, lead 124 to terminal 123, and capacitor 137 will charge an amount based on the setting of potentiometer 125.

Deenergization of relay 144 will cause its contacts 161, 162 to close, thereby completing the circuit (previously described) from capacitor 164 to the coil 175 of relay 176 to energize the latter, thereby causing switch arm 178 thereof to bridge

contacts

179 and 181. As a result, a circuit will be completed to solenoids 29 to energize the latter and lift the gate 26. The circuit is from main 93, lead 186, solenoids 29, leads 185, 184, terminal 183, lead 182, bridged

contacts

181, 179, lead 187, terminal 188, leads 191, 192, 195 to main 92.

Simultaneously with the energization of relay 176, the deenergization of relay 146 will open its

contacts

172, 173 to break the circuit from terminal 123 through

leads

166, 168, 169, 171,

contacts

172, 173, leads 230 and 234 to cathode 235 of tube 109. As a result terminal 113 will be connected to cathode 235 through

leads

112, 127, 151, 247, 251, 231, resistor 232, leads 233 and 234. As the plate 228 of tube 109 is normally connected to terminal 113, the plate 228 and cathode 235 will be at the same polarity and no current will flow through the tube. However, as the grid 241 during the positive half of the alternating current cycle will be positive with respect to cathode 235, cur-' rent will flow through grid 241, lead 242, parallel connected capacitor 243 and resistor 246, arm 244, potentiometer 245, leads 253, 254, 168, 166 to terminal 123. As a result, capacitor 243 will charge.

The cessation of current flow through tube 109 immediately deenergizes the

coils

218 and 225 of

relays

216 and 226 with the result that

contacts

215, 217 open as do contacts 259 and 264. The opening of

contacts

215, 217 breaks the circuit to the coil 212 of relay 207 so that switch arm 211 moves away from contacts 206, 208 to open the circuit to the coil 199 of the motor starter 87. As a result, the conveyer motor 14 will be deenergized and a mechanical brake (not shown) will instantly stop rotation of the motor so that there will be no further advance of discharge conveyer 13.

The simultaneous opening of contacts 259, 264 of relay 226 will break the circuit from terminal 123 to the cathode 267 of tube 111 so that terminal 113 will be connected to cathode 267 through

leads

112, 127, 147, 275, resistor 276 and lead 266. As the plate 273 of tube 111 is normally connected to terminal 113, both plate 273 and cathode 267 will be at the same polarity so that current flow through tube 111 will cease, thereby deenergizing coil 269 of relay 263.

As the grid 281 of tube 111 is connected through lead 282, parallel connected capacitor 283 and resistor 287, lead 284, arm 285, potentiometer 286, leads 293,-

168 and 166 to terminal 123, during the positive half of the alternating current cycle, current will flow through capacitor 283 to charge the latter.

Deenergization of relay 263 will close

contacts

261, 268, connecting terminal 123 to cathode 133 of tube 108 as previously described. However, due to the charge on capacitor 137 which applies a negative bias on tube 108, the latter can not conduct until suflicient time has elapsed for discharge of capacitor 137 to an amount below the cut 011 value of tube 108. This time is set for such a period to permit a desired number of sheets to stack up on the discharge conveyer at which time the cycle of operation above described will be repeated.

If the operator should desire manually to control the equipment he need merely set the selector switch so that arm 118 engages fixed contact 312. As a result, the circuit from the secondary 102 of transformer 99 to the

plates

131, 228 and 273 of

tubes

108, 109 and 111 will be broken. However, the current will still flow through the filaments, of such tubes so that the automatic control unit may instantly be switched into operation when desired without waiting for the tubes to heat.

Engagement of arm 118 with fixed contact 312 will complete a circuit from one side of the secondary winding 102 of transformer 99 through fuse 115, leads 114 and 310 to terminal 307 which is connected by lead 305 to the input terminal 303 of rectifier 302, and from the other side of secondary 102 through lead 117, arm 118, contact 312, lead 311 to terminal 308 which is connected through lead 306 to input terminal 304 of rectifier 302. Energization of the rectifier 302, which will be indicated by the illumination of lamp 309, will cause a rectified voltage to be developed across the output terminals 313 and 331.

As soon the selector switch 119 is moved to manual operation, the

movable contact arms

347, 351, 352, 354 and 353 of

relays

329, 327, 328, 326 and 325 will be connected to terminal 331 or the positive side of rectifier 302. The circuit is from terminal 331, leads 344, 32g, movable arm 347, contact 348 and common lea As a result, the coil 317 of relay 325 will be energized, the circuit being from the movable arm 354 of relay 326 which is connected to the positive terminal 331 of rectifier 302, fixed contact 382 engaged thereby, resistor 384, to one side of coil 317, and from the other side of coil 317, common lead 314 to negative terminal 313 of rectifier 302. The energization of coil 317 will move arm 353 in engagement with fixed contact 386 to close a circuit to the coil 315 of relay 323. The circuit is from arm 353 which is connected to positive terminal 331 of rectifier 302, fixed contact 386 engaged thereby, lead 387 to one side of coil 315 and from the other side of coil 315 through common lead 314 to negative terminal 313 of rectifier 302. As a result of the energization of coil 315, arm 391 will be in engagement with fixed contact 392 to complete a circuit from main 92, leads 195, 192, 398, terminal 397, lead 396,

contacts

392, 391, lead 393, terminal 394, leads 395, 185, coil of solenoids 29, lead 186 to main 93. Consequently, the solenoids will be energized to hold the gate 26 in open position so that sheets may be discharged onto conveyer 13.

In addition, when the switch 341 is. in the position shown in Fig. 2, the capacitor 337 will be connected across the filter capacitor 333 of rectifier 302 so that capacitor 337 will charge due to the connection thereacross of the output of rectifier 302.

After a desired number of sheets has been discharged onto conveyer 13 the operator may readily stop such discharge by pressing on foot switch 341.

Closing of switch 341 will move arm 339 into engagement with fixed contact 381. A circuit will be completed from one side of charged capacitor 337 through lead 338, arm 339, contact 381, lead 379, rectifier 378 (which prevents back E. M. F. from injuring the capacitor 337 which desirably is of the electrolytic type), lead 377,

contacts

369, 371 of relay 368, lead 374, coil 318 of relay 316, leads 335 and 336 to the other side of capacitor 337. As a result, coil 318 will be energized.

Energization of coil 318 will open

contacts

354, 382 of relay 326 to break the circuit to the coil 317 of relay 325. Consequently,

contacts

352, 386 will open to break the circuit to coil 315 of relay 323 and

open contacts

391, 392 thereof to break the circuit to solenoids 29, thereby to lower the gate and stop further discharge of sheets. The momentary energization of relay 326 by the pulse from capacitor 337 will complete a circuit from arm 354 which is connected to positive terminal 331 of rectifier 307, contact 376, lead 375, coil 372 of relay 368, lead 374, coil 318 of relay 326 to common lead 314 connected to negative terminal 313 of rectifier 302. As a result, a holding circuit will be provided for

relays

368 and 326, so that arm 377 will engage contact 367 and arm 354 will engage contact 376.

After sufiicient time has elapsed for the last sheet to pass through the closed gate onto conveyer 13, the operator can again press switch 341 which will be in the position shown with arm 339 engaging fixed contact 345.

As a result, another charge which has been built up on capacitor 337 will pass from one side of capacitor 337 through lead 338,

contacts

339 and 381, lead 379, rectifier 378, lead 377,

contacts

369 and 367 of relay 368, lead 366,

contacts

359 and 357 of relay 358, lead 356 through coil 319, common lead 314, leads 335 other side of capacitor 337. The momentary energization of coil 319 will complete a circuit from arm 351 connected to the positive terminal 331 of rectifier 302, contact 364, lead 363 through coil 362 of relay 358, lead 356, coil 319 to common lead 314 connected to the positive terminal 313 of rectifier 302. The holding circuit thus provided will retain arm 359 against contact 361 and arm 351 against contact 364. Movement of arm 351 against contact 364 will break the circuit to the coil 321 of relay 328 to bring arm 352 into engagement with fixed contact 388. This will complete a circuit from positive terminal 331 of rectifier 302 to which arm 352 is connected, through lead 389, coil 316 of relay 324 to common lead 314, and negative terminal 313. Energization of relay 324 will bring arm 401 into engagement with fixed contact 402 to complete a circuit to the coil 199 of the motor switch 87. The circuit is from main 93, fixed contact 89, coil 199, leads 198, 203, 404, terminal 403, contacts 402, 401, leads 399, terminal 397, leads 398, 192, 195 to main 92. Energization of coil 199 will close motor switch 87 thereby to complete a circuit to the conveyer motor 14 to move the stack of sheets thereon past the gate 26. When this has ccurred, the operator can again step on switch 314 which will deliver a pulse from the charged capacitor 337 to the coil 322 of relay 329. The circuit is from one side of capacitor 337, lead 338. switch 34-1, lead 379, rectifier 378, lead 377,

contacts

369, 367, lead 366,

contacts

359, 361, lead 360, coil 322, lead 314, 335. 336 to the other side of capacitor 337. Energization of coil 322 will move arm 347 away from contact 348 to break the connection from positive terminal 331 of rectifier 302 to the arms 351 and 3554 thereby breaking the holding circuits above described which will break the circuit to the solenoids 29 to raise gate 26 and to the motor coil 199 to deenergize motor 14 so that sheets will and 336 to the 10 again be discharged on the now stationary conveyer 13.

Where the operator wishes to keep the conveyor 13 running continuously so that individual sheets may be discharged therefrom and with selector switch 119 preferably in manual position, the operator need merely close motor switch 194 to effect energization of coil 199 of motor switch relay 187.

As many changes could be made in the above construction, and many apparently widely diiferent embodiments of this invention could be made without departing from the scope of the claims, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In an article feeding and stacking apparatus of the type comprising a discharge conveyer to receive such articles for stacking, drive means for said conveyer and a gate to control the discharge of such articles onto said discharge conveyer; the combination therewith of a vacuum tube, a parallel connected resistor capacitor timer in the grid circuit of said tube, circuit means to charge said capacitor to apply cut oil bias to said tube, a solenoid to control said gate, means normally completing a circuit to said solenoid when said tube is cut off to retain the gate in open position for discharge of such articles onto said conveyer and opening the circuit to said solenoid after said capacitor has discharged through said resistor and said tube conducts to deenergize the solenoid to close said gate, means to energize the drive means for said conveyer a predetermined length of time after said gate has closed, means independent of said capacitor to cut ofi said vacuum tube a predetermined length of time after said drive means has been energized thereby to complete the circuit to said solenoid to energize the latter and open the gate, means controlled by the cutting off of said vacuum tube to deenergize the drive means simultaneously with the opening of said gate and to remove the independent means cutting ofi said vacuum tube, whereby after said capacitor has discharged through said resistor to reduce the bias on said tube to a point below its cut off value, said tube will conduct.

2. In an article feeding and stacking apparatus of the type comprising a discharge conveyer to receive such articles for stacking, drive means for said conveyer and a gate to control the discharge of such articles onto said discharge conveyer; the combination therewith of a vacuum tube, a parallel connected resistor capacitor timer in the grid circuit of said tube, circuit means to charge said capacitor to apply cut off bias to said tube, a solenoid to control said gate, means normally completing a circuit to said solenoid when said tube is cut oil to retain the gate in open position for discharge of articles onto said conveyer and opening the circuit to said solenoid after said capacitor has discharged through said resistor and said tube conducts to deenergize the solenoid to close said gate, means to energize the drive means for said conveyor a predetermined length of time after said gate has closed, means to apply potential of the same polarity to the plate and cathode of said vacuum tube to cut off the latter a predetermined length of time after said drive means has been energized thereby to complete the circuit to said solenoid to energizethe latter and open the gate, means controlled by the cutting off of said vacuum tube to deenergize the drive means simultaneously with the opening of said gate and to apply potential of different polarity to the plate and cathode of said vacuum tube, whereby after said capacitor has discharged through said resistor to reduce the bias on said tube to a point below its out off value, said tube will conduct.

3. In an article feeding and stacking apparatus of the type comprising a discharge conveyer to receive such articles for stacking, drive means for said conveyor and a gate to control the discharge of articles onto said conveyer; the combination thereof of an automatic control circuit comprising three vacuum tubes, a solenoid to control said gate, means controlled by the first of said tubes to energize and deenergize said solenoid to raise and lower said gate when said first tube is in a non-conducting and conducting state respectively, means controlling said first tube to effect conduction thereof to lower said gate a predetermined length of time after said gate is raised, means controlled by said first tube to apply a potential of different polarity to the plate and cathode of said second tube when said first tube is conducting and a potential of the same polarity when said first tube is not conducting, means controlled by said second tube to energize and deenergize said drive means when said tube is in a conducting and non-conducting state respectively, means controlling said second tube to effect conduction thereof a predetermined length of time after said gate is lowered thereby to energize said drive means and advance said conveyer, means controlled by said second tube to apply a potential of different polarity to the plate and cathode of said third tube when said second tube is conducting and a potential of the same polarity when said second tube is not conducting, means controlled by said third tube to apply a potential of different polarity to the plate and cathode of said first tube when said third tube is not conducting and a potential of the same polarity when said third tube is conducting, means controlling said third tube to effect conduction thereof a predetermined length of time after said drive means is energized, whereby said first tube will be cut off to raise said gate and cut off said second tube to deenergize said drive means and the cut ofi of said second tube will cut off said third tube to apply different potential to the plate and cathode of said first tube.

4. The combination set forth in claim 3 in which the means controlling said tubes to effect conduction thereof comprises a parallel connected resistor capacitor timer in the grid circuit of each of said tubes respectively.

5. The combination set forth in claim 3 in which the means controlling said tubes to effect conduction thereof comprises a parallel connected resistor capacitor timer in the grid circuit of each of said tubes respectively and a potentiometer is provided in circuit with said capacitor in order that a predetermined charge may be applied thereto.

6. The combination set forth in claim 3 in which the means controlled by the first of said tubes to energize and deenergize said solenoids comprises a relay in the plate circuit of said tube having a pair of contacts normally closed when said tube is not conducting and a second relay controlled by said first relay and completing a circuit to said solenoids when said contacts are closed.

7. The combination set forth in claim 3 in which circuit means are provided to connect the plate of said second and third vacuum tubes to one pole of a source of potential and normally to connect the cathode of said tubes to the other pole of said source of potential and a relay is provided in the plate circuits respectively of said first and second tubes, each of said relays having a pair of contacts normally open when said tubes are not conducting, one of said contacts of each of said pairs being connected respectively to the other pole of said source of potential and the other contact of each of said pairs being connected to the cathodes of said second and third tubes respectively, whereby upon conduction of said first and second tubes and energization of the associated relays, the open contacts will be closed.

8. The combination set forth in claim 7 in which a resistor is provided in series with the cathode and the other pole of said source of current and said other contact of each of said pairs of contacts is connected to the associated cathode between said cathode and said resistor.

9. The combination set forth in claim 3 in which circuit means are provided to connect the plate of said first vacuum tube to one pole of a source of potential and a relay is provided in the plate circuit of said third tube, said relay having a pair of contacts normally closed when said third tube is not conducting, one of the contacts of said relay being connected to the other pole of such source of potential and the other contact being connected to the cathode of said first tube whereby the cathode of said first tube will normally be connected to the other pole of said source of potential when said third tube is non-conducting and upon conduction of said third tube and energization of said relay to break the circuit to the cathode of said first tube, said contacts will be opened.

10. The combinations set forth in claim 3 in which the means controlled by said second tube to energize and deenergize said drive means comprises a relay in the plate circuit of said second tube having a pair of contacts normally open when said tube is not conducting, a second relay controlled by said first relay and energized when said tube is conducting and a motor relay controlling said drive, means and energized when said second relay is energized to complete a circuit to said drive means.

ll. The combination set forth in claim 3 in which a manual control circuit is associated with said automatic control circuit, and switch means are provided to connect one or the other of said control circuits to operate said equipment.

12. In an article feeding and stacking apparatus of the type comprising a discharge conveyer to receive such articles for stacking, drive means for such conveyer and a gate to control the discharge of articles onto such conveyer; the combination therewith of a relay to control said gate, said relay when energized retaining the gate in open position, a second relay controlling said drive means and retaining the latter deenergized when said second relay is deenergized, a capacitor, switch means normally connecting said capacitor to a source of current to charge the same and movable from such charge position to discharge position, means upon movement of said switch to discharge position to deenergize said gate relay to lower said gate and provide a holding circuit for said gate relay whereby upon return of said switch to charge position, said gate will remain lowered, means upon subsequent movement of said switch to discharge position to energize said drive relay to energize said drive means and advance said conveyer, and provide a holding circuit for said drive relay whereby upon return of said switch to charge position said drive relay will remain energized, and means upon subsequent movement of said switch to discharge position to open said holding circuit thereby to energize said gate relay to lift said gate and to deenergize said drive relay to deenergize said drive means and stop said conveyer whereby upon return of said switch to charge position the cycle can be repeated.

13. The combination set forth in claim 12 in which the means to deenergize said gate relay comprises a normally energized relay having a coil and a pair of closed contacts completing a circuit to said gate relay, a normally deenergized relay having a coil in circuit with the discharge position of said switch and having a fixed contact and a movable contact arm normally engaging said fixed contact and completing a circuit from such source of current to said normally energized relay whereby upon movement of said switch to discharge position said normally deenergized relay will be energized to move the movable arm thereof away from said fixed contact to open the circuit to the coil of said normally energized relay thereby to open the contacts thereof and breaking the circuit to said gate relay to deenergize the latter.

14. The combination set forth in claim 13 in which said normally deenergized relay has a second fixed contact engaged by said movable arm when said relay is energized, said movable arm being connected to one side of such source of current, and a fourth relay is provided having a coil connected on one side to said second fixed contact and on its other side to one side of the coil of said normally deenergized relay, the other side of which is connected to the other side of such source of current whereby when said normally deenergized relay is energized and the movable arm thereof engages said second fixed contact, the coils of said fourth relay and said normally deenergized relay will be energized to provide the holding circuit for said gate relay to retain the gate in closed position.

15. The combination set forth in claim 14 in which said fourth relay has a movable switch arm connected to the discharge position of said switch and a second fixed contact normally spaced therefrom when said fourth relay is deenergized and connected in circuit with the means to energize said drive relay, whereby upon energization of the coil of said fourth relay and movement of the movable arm thereof into engagement with said second fixed contact, the means to energize said drive relay will be connected in circuit with the discharge position of said switch so that said drive relay can be energized only after said gate relay has been deenergized.

16. The combination set forth in claim 15 in which said drive relay has a coil connected at one end to one side of such source of current and the means to energize said drive relay comprises a normally energized relay having a coil, a fixed contact and a movable arm connected to the other side of such source of current and spaced from said fixed contact, the latter being connected to the other end of the coil of said drive relay, a normally deenergized relay having a coil in circuit with the second fixed contact of said fourth relay, and having a fixed contact and a movable contact arm engaging said fixed contact to complete a circuit from such source of current to said normally energized relay, whereby upon movement of the movable arm of said fourth relay into engagement with said second fixed contact, and movement of said switch to discharge position, said normally deenergized relay will be energized to move the movable arm thereof away from the fixed contact to open the circuit to the coil of said normally energized relay to bring the movable arm thereof into engagement with the fixed contact to complete a circuit to the'drive relay.

17. The combination set forth in claim 16 in which said normally deenergized relay has a second fixed contact engaged by said movable arm when said relay is energized, said movable arm being connected to one side of such source of current, and a second holding relay is provided having a coil connected on one side to said second fixed contact and on its other side to one side of the coil of said normally deenergized relay, the other side of which is connected to the other side of said source of current, whereby when said normally deenergized relay is energized and the movable arm thereof engages said second fixed contact, the coil of said second holding relay and said normally deenergized relay will be energized to provide the holding circuit for said drive means to retain the latter energized.

18. The combination set forth in claim 17 in which said second holding relay has a movable switch arm connected to the second fixed contact of said first holding relay, and a second fixed contact normally spaced therefrom when said second holding relay is deenergized, a control relay is provided having a coil connected on one side of said second fixed contact of said second holding relay and on its other side to said capacitor, said control relay having a pair of closed contacts in series with the source of current and the movable arms of said normally energized and normally deenergized relays, whereby when said first and second holding relays are energized and said switch is moved to discharge position said control relay will be energized to break the circuit to said movable arms, thereby to break the holding circuit and to energize the gate relay to lift the gate and deenergize the drive relay to deenergize the drive means.

Name Date Morrison May 2, 1950 Number