US3189178A

US3189178A - Article sorting machine

Info

Publication number: US3189178A
Application number: US230839A
Authority: US
Inventors: Donald A Calleson; William R Weidlich
Original assignee: Liggett and Myers Tobacco Co
Current assignee: Liggett Group LLC
Priority date: 1962-10-16
Filing date: 1962-10-16
Publication date: 1965-06-15
Anticipated expiration: 1982-06-15

Description

June 15, 1965 D. A. CALLESON ETAL ARTICLE SORTING MACHINE Filed Oct. 16, 1,962 4 Sheets-Sheet 1 TiTl.

D. A. CALLESON ETAL 3,189,178

ARTICLE SORTING MACHINE June 15, 1965 4 Sheets-Sheet 2 Filed Oct. 16, 1962 3 V//// /M V////4 INVENTORS 00mm A. CALZIFSON BY W/LA/AM A, am/cw June 15, 1965 4 Sheets-Sheet 3 Filed Oct. 16, 1962 INVENTORS DOA/141D A 041L550 BY W/LL/fl/V P. WE/DZ/C/l TOTA L 44770 NEKY wf w J1me 1965 D. A. \CALLESON ETAL 3,189,178

ARTICLE SORTING MACHINE 4 Sheets-Sheet 4 Filed Oct. 16, 1962 INVENTORS DOA/A10 0/711 ESON BY W/LL MM R h/E/OL /CA AT 7 A/EVS United States Patent 3,189,178 ARTICLE SORTING MACHINE Donald A. Calleson and William R. Weidlich, Durham, N.C., assignors to Liggett & Myers Tobacco Co., New York, N.Y., a corporation of New Jersey Filed Oct. 16, 1962, Ser. No. 230,839 1 Claim. (Cl. 209121) This invention relates in general to machines for segregating articles by weight ranges and more particularly to a cigarette sorting machine that can be used in conjunction with statistical quality control in that it will weigh cigarettes, indicate the number of cigarettes out of sample in each of a number of weight ranges, and segregate all the cigarettes in the sample into a number of bins that correspond to the weight ranges so that further testing of the cigarettes in any given range may be had.

Machines are available which will weigh cigarettes, one at a time, and will provide, through a series of counters, an indication of the number of cigarettes in the sample fed to the machine which fall within pre-selected weight intervals. These machine, however, do not segregate the cigarettes in the sample involved into groups that correspond to each of the many weight intervals. Thus no means is provided for further testing of those cigarettes that fall within any one or more of the weight intervals measured.

It is important that the cigarettes in the sample on test be physically segregated into weight intervals as well as having their weights recorded by weight intervals. The determination of tobacco filling power requires weight segregation. Filling power is a function of the firmness of a cigarette at a given cigarette weight to volume ratio. Thus the cigarettes must be segregated into fairly narrow weight groups in order to make filling power determinations. In general, the quality control process is greatly enhanced by an ability to test cigarettes within selected weight ranges.

Accordingly, it is a major object of this invention to provide an automatic cigarette sorting machine that will sort all'the cigarettes fed to it into a large number of pre-selected weight intervals.

It is another object of this invention to provide such a sorting device in conjunction with an automatic cigarette weighing machine.

It is another object of this invention to provide such a device wherein the number of weight intervals and the span of each weight interval may be readily changed.

In brief, this invention involves a fairly standard storage hopper and drum feeder which are positioned to feed cigarettes one at a time onto the balance pan of an electronic balance. The electronic balance provides an electrical signal, the magnitude of which is a direct function of the weight of the cigarettes in the balance pan. This electronic signal is then fed through an adjustable balancing network to cause a further signal to be fed to a null seeking servo motor. The servo motor is mechanically ganged to a variable potentiometer which forms the adjustable part of the balancing network. The variable arm on the potentiometer is thus rotated by the servo motor until the potentiometer causes the network to balance out the indicating signal from the electronic balance. When the network is in balance no signal is provided to the servo motor and thus the motor ceases to rotate.

Also ganged to the servo motor is a contact arm which describes a circular arc in response to the movement of the servo motor. One end of the arm makes electrical contact with a series of metal contact strips, insulated from one another, deployed in the arc, so that the contact arm makes contact with one of these strips at a time. Each strip is electrically connected to a separate one of a series of counters. After the servo motor comes to rest, a timer cam actuates a relay to close a relay contact and complete the contact arm-counter circuit so that a signal is provided to the appropriate counter.

Also ganged to the servo motor is a sorting chute which has an upper end disposed adjacent to the balance pan and a lower end disposed adjacent to one of a series of bins deployed in an arc. As the servo motor rotates, the sorting chute rotates so as to provide a chute communication between the balance pan and an appropriate one of the bins. After the motor ceases to rotate, a timer cam actuates a solenoid that causes an ejector arm to push the cigarette being weighed into the top of a sorting chute so that, by gravity and momentum feed, the cigarette is deposited in the appropriate bin.

Thus the bin into which the cigarette being weighed is deposited and the particular counter which registers the fact of a cigarette being on the balance pan are determined by the position of a servo motor, which motor position is in turn determined by the magnitude of the electronic balance output signal and thus is determined by the weight of the cigarette. In this fashion, the number of cigarettes within each of a series of pre-selected weight intervals is recorded and the cigarettes are collected in separate bins that represent these weight intervals. The whole process is done automatically, requiring only that the operator load the hopper with the desired sample of cigarettes.

Other objects and purposes of this invention will become apparent from a consideration of the drawings and detailed descriptions, in which:

FIG. 1 is a front view, partly in elevation and partly in section, of the device of this invention;

FIG. 2 is a view along the plane 2-2 in FIG. 1, showing a cigarette in the balance pan in position to be ejected into the feeding chute;

FIG. 3 is a view along the plane 33 in FIG. 2; FIG. 4 is a partial plan view along the plane 44 in FIG. 1, showing a cigarette being fed into one of the bins by the feeding chute;

FIG. 5 is a mechanical and electrical schematic diagram showing the mechanical linking between the servo motor, the variable potentiometer and the feeding chute; and also showing the circuitry for feeding counting impulses to the appropriate counters; and

FIG. 6 is an electrical block and schematic diagram illustrating the electrical circuitry involved in the device of this invention.

Referring now to FIG. 1, a sample of cigarettes 10 is shown in a hopper 11. A rotating, fluted, feeding drum 12 is located directly below the hopper 11 outlet 13. The hopper outlet 13 is wide enough to permit only one cigarette 10 at a time to be fed to the feeding drum 12. As the drum 12 rotates, its flutes 14 pick up cigarettes 10 one at a time and carry the cigarettes around to be deposited in a balance pan 16 of an electronic balance 17. The wall 18 prevents the cigarettes from falling out of the flutes 14 until the cigarettes 10 are positioned over the balance pan 16.

When a cigarette 10 is deposited in the balance pan 16, the electronic balance 17 provides, a DC. output signal which is then fed to a balancing network, the exact circuitry of which will be described in greater detail further on. Suffice it to say here that a null seeking servo motor 22 is connected to the electrical balance network. When the network is unbalanced by the output of the electronic balance 17 a signal is provided to the servo motor 22. This null seeking servo motor 22 is mechanically ganged to the variable arm of a potentiometer 23, which potentiometer 23 forms part of the balance network to which the servo motor 22 is electrically connected. Thus as the servo motor 22 rotates in response to the unbalance in the balance network, the potentiometer 23 is varied until it reaches a position and value that causes the network to balance and con equently causes the null seeking servo motor 22 to cease rotating. In this fashion, the amount of rotation of the servo motor 22 is a function of the magnitude of the electronic balance 17 output and consequently a function of the weight of the cigarette that is in the balance pan 16.

As may best be seen in FIG. 4, a series of bins 25 are deployed in a circular arc around the axial shaft 27 of the servo motor 22. These bins 25 are at a level lower than that of the balance pan 16 so that the cigarette 19 may be fed from the balance pan 16 to the bins 25 in the manner that will be described hereafter. As shown in the drawings, the bins form an arc of a circle but not a complete circle around the shaft 27.

A two-part chute 26 is used to deliver cigarettes from the balance pan 16 to the bins 25. As may best be seen in FIG. 2, the upper portion 26A of the chute 26 serves to direct the ejected cigarette 16 through a 90 turn so as to enter the mouth of lower portion 268. The lower portion 26B of the chute 26 is a curved, partially cut-away tube, the lower end of which hovers over the bins 25. The lower portion 26B of the chute 2a is mounted at its own upper end on the servo motor 22 shaft 27. The lower portion 26B is supported by the shaft 27 and mates with but is not connected to upper portion 26A. Thus the lower portion 263 is free to rotate with little frictional resistance. The particular bin 25 over which the chute 26 hovers will depend upon the rotation of the servo motor 22 shaft 27. 'Since the angular rotation of the shaft 27 is a function of the magnitude of the electrical signal output from the balance 17, the particular bin 25 that will be in communication with the balance pan 1-6 through the chute 26 will depend upon the weight of the cigarette 10 that is in the balance pan 16.

The mechanical aspects of the ejection system are illustrated in FIGS. 2 and 3. A disk face 28 mounted on a shaft extension 29 is connected to a solenoid 30 core. The solenoid 30 is mounted with its axis coincident with that of the cigarette 10 being weighed. In a pre-determined time period after the cigarette 10 is deposited in the balance pan 16 a signal is fed to the solenoid 30 which causes the shaft 29 and disk 28 to kick the cigarette 10 off the pan 16 into the chute 26. Gravity and momentum assures that the cigarette 10 will then travel down the chute 26 to the appropriate bin 25. The pre-determined time interval during which the cigarette 10 is left on the balance pan 16 is a period of time that is correlated to the speed of the feeding drum 12 and to the time it takes for the servo motor 22 to rotate the chute 26 into communication with the appropriate bin 25. As will be de-' scribed later, a rotating cam performs this timing function.

The 90 turn in the upper portion 26A of the chute 26 makes possible the rotation of the lower ends of the chute while the upper end of the chute remains fixed adjacent to the balance pan 16.

In conjunction with the, technique above described for delivering cigarettes 10 by weight intervals to appropriate bins 25, there is provided-a means to record the number of cigarettes delivered to each bin 25 on counters. FIGS. 2 and 5 best illustrate the counter connection. A series of conducting strips 32 (distinguished from each other as 32a through 32v) are deployed in an arc around the shaft 27 of the servo motor 22 and thus form an arc concentric with the arc of the bins 25. 'Each of these conducting strips 32 is connected toa separate counter 33. The counters 33 are then connected through a total izing counter 34, a normally open relay contact 35d, and a source of DC. power 36 to a conducting wiper arm 37 which arm is mechanically mounted to the shaft 27 of the servo motor amplifier '41.

servo motor 22. The wiper arm 37 is mounted on the shaft 27 by an insulator 38 so that the circuit just de scribed is insulated from the rest of the control circuitry. The end of the wiper arm 37 makes electrical contact with the conducting strips 32. The mechanical mounting of the shaft end of the wiper arm 37 to the motor shaft 27 causes the wiper arm 37 to complete a circuit through a particular conducting strip 32 and thus a particular counter 33 that will be correlated to the weight of the cigarette 10 on the balance pan 16. A standard brushslip ring combination may be used to provide electrical contact between the wiper arm 37 and the relay contact 35a. 7 N

The selective operation of the wiper arm 37 is identical with the selective operation of the chute 26. Both are mounted on the shaft 27 of the servo motor 22, which motor 22 rotates by an amount that corresponds to the output signal of the electronic balance 17 for reasons described above that relate to the position of the poteniometer 23 in a balancing network to which this null seeking servo motor 22 is connected.

When a cigarette 10 is deposited in the balance pan 16, a signal output causes the servo motor 22 to rotate and thus rotate the wiper arm 37. After themotor has achieved a stable position and the wiper arm 37 is, ac-

cordingly, connected to the appropriate conducting strip 32, the cam 50 opens 51 to interrupt power to the relay 35 thereby causing contact 35a to close and contact 35b to open. (The rotating cam 5t) time delay mechanism that actuates the relay 35 is described in conjunction with the description of FIG. 6 hereafter.) As the contact 35a closes, a circuit is completed which provides a pulse of DC. current from the charged capacitor C to cause the particular counter 33 which is connected to the conducting strip 32 on which the wiper arm 37 rests, to count one. A-totalizing counter 34 also counts one so that the total of all the counters 33 will equal the reading on the counter 34. V I

:FIG. 6 illustrates the electrical circuit which makes possible the proper timing and sequence of events described above. It is particularly impontant that the sole noid 3t} not operate'until after the chute 26 and wiper arm 37 have been rotated to the apporpriate bin 25' and conducting strip 32, respectively. It is also important that the contact 35a not'be closed until after the wiper arm 37 has reached its final position so that there will be no false readings on the counters 33. It is also important that the servo motor 22 circuit be open at the time of ejection so that the electrical unbalance resulting from the romoval of the cigarette 10 from the balance pan 16 does not reposition the servo motor 22 before the cigarette can be properly deposited in a bin 25.

The electronic balance 17 involved is a standard electronic balance and thus is indicated in FIG. 6 as a block. The balance 17 should provide a DC. output, the voltage of which is proportional to the weight being registered. The greater the linearity between balance 17 output and weight registered, the greater will be the accuracy of the sorting operation. The circuitry, within the dotted lines, designated by the numeral 40, operates as an electrical balancing network. The output terminals X-X of the electronic balance 17 from the input terminals to the network 40, while the terminals YY can be considered the output terminals of the network 40; The output of the network 40 is fed to the servo motor 22 through a The potentiometer 23 forms part of the circuitry within the balancing network 40 and, as hasbeen described above, the potentiometer 23 is a variable potentiometer which is ganged to the shaft 27 of the servo motor 22. The servo motor 22 can be considered a null seeking servo motor in that it will respond to any input signal and continue to rotate until 01 unless the input signal to the servo motor 22 becomes zero.

The transformers 42 and capacitors 43 serve to eliminate A.C. current from the rest of the network 40.

The battery 44 establishes a gradient across the potentiometer 23. Thus of the DC. voltage, from the electronic balance 17, that is fed to the potentiometer wiper a-rm 23a exactly equals the voltage at the point where the wiper arm 23a contacts the potentiometer 23, then no current will flow through the circuit 40 as a consequence of the voltage from the electronic balance 17. Consequently, no current will be supplied to the servo amplifier 41 and the servo motor 22 will not rotate. Conversely, if current is supplied to the servo motor 22, the wiper arm 23a will rotate until it reaches a potential on the potentiometer 23 that is exactly equal to the voltage being fed to the wiper arm 23a from the electronic balance 17. In one embodiment it has been found desirable to replace the battery 44 with a regulated power supply. The constant voltage source required is shown as a battery 44 for simplicity.

When there is unbalance in this network 40, current fiows from the electronic balance 17 to the wiper arm 23a, through the potentiometer 23 and the resistors R R R and R The variable arm 56 taps a signal from R; as a consequence of this unbalanced current to provide an unbalance current in R A further tap on R provides a signal to the servo amplifier 41 to power the servo motor 22. When there is balance, no such current can flow. Current cannot be supplied to the servo motor 22 from the battery 44 since there is no return path to the battery 44 through the amplifier 41 or the servo motor 22.

The feeder motor 12M rotates the fluted feeding drum 12 and is run at some relatively slow speed such as 5 r.p.m. A rotating interrupter cam 50, having as many high points as the feeding drum 12 has flutes 14, is also driven by the feeder motor 12M. The cam 50 thus interrupts a circuit to the relay 35 at the same rate as cigaretts are deposited on the balance pan 16. FIG. 6 shows relay 35 in an excited state, which state obtains while the cigarette 10 is being weighed, the chute 26 is rotating, and the motor 22 is seeking a null position. In the state shown, the closed contact 35b permits the capacitor C to become charged. When the cam 50 causes the switch 51 to open, the relay 35 becomes de-energized and the contact 35b opens while the contact 35a closes. The charge on the capacitor C is then discharged through the ejection solenoid 30, the totalizing counter 34 and the appropriate one of the individual counters 33. The wiper arm 37, described in conjunction with FIG. 5, is shown schematically in FIG. 6. Concurrently, the contact 35c opens breaking the circuit to the servo motor 22 so that the chute 26 and wiper arm 37 will remain stationary during the weight recording and sorting operation. It is particularly important that the servo motor 22 not respond to the weight change in the balance pan 16 as the cigarette 10 is ejected into the chute 26. Thus the contact 35c opens to assure that the chute 26 will remain at the proper bin 25 while the cigarette is traversing the chute 26.

The manually operated sorter switch 5 2 is normally closed, as shown, when the machine is in operation. The switch 52 is opened to protect the servo system components when this sorting device is not in operation.

There are certain adjustments in the network 40 which should be undestood for a complete comprehension of this invention.

The first adjustment that will be discussed affects the span of the chute 26 are. The position of the variable contact 55 leading from the potentiometer 23 to the resistor R affects the span (angular displacement of the chute 26B per weight increment). The span will be increased as the arm contact 55 is moved up along the resistor R as shown in FIG. 6. Roughly speaking, the span will be increased because the potentiometer 23 voltage has been decreased; therefore, the wiper arm 23a must travel further to counter-balance a given increment of balance voltage (weight).

A zero suppression or tare control (slider 56 of potenti'ometer R4 in FIG. 6) is used to offset the weight range without affecting the span; for example, a weight range of 1.000 to 1.400 could be changed to 0.900 to 1.300 (grams) or to 1.100 to 1.500 (grams) by adjusting the tare control. The wiper arm 37 is allowed to rotate slightly beyond contact 32a in the clockwise direction in order to eliminate false counts when the pan 16 is empty. The cam 50 will continue to operate as long as the drum 12 rotates even though no cigarettes are being fed.

To stop a moving mass at a given point, braking force must be applied before that point is reached; otherwise the object will overshoot its mark. For a given mass and a given braking force, the stopping distance is proportional to speed. If the position can be represented (as in this device) by a DC. voltage, then an opposing DC. voltage proportional to speed can be added to anticipate the required stopping distance. This latter voltage is supplied by the tachometer generator 58. A voltage-divider (the potentiometer 23) controls the voltagespeed relationship of the generator system so that rapid sorting with minimum overshoot is possible.

The system illustrated is quite stable and free from electrical drift, requiring recalibration maybe once a day if the power is allowed to remain on. Calibration is very rapid and can be easily accomplished at the beginning of each run. Calibration time is approximately 30 seconds at the most. Under these conditions the accuracy of the instrument is within :2 milligrams. On the basis of a cigarette mean weight of 1000 milligrams the weighing accuracy could be expressed as i0.2%. The sorting accuracy of the instrument would be determined by the percentage of cigarettes in a given collection bin 25 which fall outside the bin weight limits. There is found to be some overlap between bins, however, and an accuracy figure based purely on the number percentage being correctly placed in a bin may therefore sometimes be quite high. The weight percentage that these cigarettes differ from the bin mean weight would therefore be a more realistic measure. On this basis the sorting accuracy is approximately i0.5%.

The above particular description is but one embodiment of this invention. It should be obvious to those skilled in this art that many variations may be made without departing from the scope of this invention.

For example, the balancing network 40 illustrated and described has been found to be particularly adapted to the application illustrated. However, a wire variety of balancing circuits might be used.

Certainly items other than cigarettes may be weighed and sorted by the device of this invention. For some such items gravity feed may not be optimum. Ball bearings, for example, could be weighed and given sufficient kick by the solenoid 30 to roll up an upwardly inclined chute.

Moreover, the sorting system could be used to classify items in terms of variables other than weightas long as such variable was: (a) voltage, or (b) converted voltage by an appropriate transducer. For example, resistors could be matched to close tolerancesof the order of 0.10%by using an appropriate test voltage source and a Wheatstone bridge.

We claim:

A cigarette sorting machine comprising a hopper to receive a desired sample of cigarettes,

a fluted feeding drum beneath said hopper to receive cigarettes from said hopper,

an electronic balance having a balance pan to provide a signal that is a function of the weight being registered on said balance pan, the balance pan of said balance being located under said feeding drum to receive cigarettes from said drum,

a series of collection bins deployed in an are at a level lower than said balance pan,

a feeding chute having an upper end disposed adjacent to said balance pan and a lower end disposed adja- '0 a 0 cent to said bins whereby one of said cigarettes i by the number of cigarettes deposited in each bin ejected into the upper end of said feeding chute will may be separately counted i b f d to o of id bin i t d b it f d, e ection means for transferring a cigarette from said balancing pan to said upper end of said chute, and

tinting means correlated to the rotational speed of said feeding drum to initiate the operation of said counting means and of said ejection means after said servo means has pivoted said lower end of said chute to the appropriate one of said bins.

said feeding chute having a lower portion and an upper portion, said lower portion being pivotally mounted 5 to permit changing the location of said lower end of said chute along said are of said bins, said upper portion permitting said lower portion to pivot while said upper end is held'in fixed relationship to said bala e v 1 10 References Cited by the Examiner servo means linked to said lower portion of said feed- UNITED STATES PATENTS ing chute and responsive to said signal to pivot said; 1 743 939 1/30 Thomas 193 23 lower end of said chute to a position along said are 2:417:642 3/47 Gilchrist 209 121 of said bins that is correlated to the weight being 15 2,537,628 1/51 Hanson registered 2,790,549 4/57 'Bize 209. 21 counting means linked to said lower portion of said 2331403 5 /58 Norris 209 1115 chute to register a count each time that a cigarette is o weighed, said counting means including a separate SAMUEL COLEMAN Primary Exammer' counter corresponding to each one of said bins where- 20, ROBE B- V Examiner-