US3604429A

US3604429A - Cigarette-dense-end-measuring method and apparatus

Info

Publication number: US3604429A
Authority: US
Inventors: John E De Witt
Original assignee: Industrial Nucleonics Corp
Current assignee: Industrial Nucleonics Corp; ABB Automation Inc
Priority date: 1969-10-03
Filing date: 1969-10-03
Publication date: 1971-09-14
Anticipated expiration: 1988-09-14

Abstract

The location of dense tobacco regions relative to the ends of cut cigarettes is determined by a density gauge positioned adjacent to a moving tobacco rod prior to cutting in a cigarette making machine and located therein by means of a signal from the density gauge which is divided by an electronic gating circuit into two components, one representative of the density of that portion of the rod that will provide the ends of the cut cigarettes and the other representative of that portion of the rod that will lie intermediate the ends. The signal components are averaged and an output signal proportional to their difference is obtained to indicate correct synchronization of the cigarette cutter with the dense end device. Pulses from the cutter may be presented simultaneously on a dual channel oscilloscope with the density signal to visually indicate an outof-phase condition. Alternately, an out-of-phase condition may be indicated on a meter arranged in parallel with an alarm.

Description

United States Patent [72] Inventor John E. De Witt Columbus, Ohio 121] App]. No. 864,292 {221 Filed Oct. 3, 1969 [45] Patented Sept. 14, 1971 [73] Assignee Industrial Nucleonics Corporation Continuation of application Ser. No, 544,000, Apr. 20, 1966.

{54] ClGARETTE-DENSE-END-MEASURING METHOD AND APPARATUS 19 Claims, 4 Drawing Figs.

[52] US. Cl 131/21, 131/65, 131/84, 146/104 [51] 1nt.Cl A24c 5/18, A24c 5/28 [50] Field 01 Search 131/21,21 B,21 D, 84, 84C, 61, 61 A,61 13,63,64, 65; 146/1, 104

[5 6] References Cited UNITED STATES PATENTS 1,567,533 12/1925 131/65 1,851,334 3/1932 131/65 1,920,708 8/1933 131/65 1,968,018 7/1934 131/63 2,316,213 4/1943 l31/61UX 2,290,896 7/1942 131/61 B 2,338,070 12/1943 Lopez 131/21UX 2,543,277 2/1951 Copeman 131/6 3 X Primary Examiner-Joseph S Reich Att0rneysWi1liam T. Fryer, 111, C. Henry Peterson and James J. OReilly ABSTRACT: The location of dense tobacco regions relative to the ends of cut cigarettes is determined by a density gauge positioned adjacent to a moving tobacco rod prior to cutting in a cigarette making machine and located therein by means of a signal from the density gauge which is divided by an electronic gating circuit into two components, one representative of the density of that portion of the rod that will provide the ends of the cut cigarettes and the other representative of that portion of the rod that will lie intermediate the ends. The signal components are averaged and an output signal propos= tional to their difference is obtained to indicate correct synchronization of the cigarette cutter with the dense end device. Pulses from the cutter may be presented simultaneously on a dual channel oscilloscope with the density signal to visually indicate an out-of-phase condition. Altemately, an out-of-phase condition may be indicated on a meter arranged in parallel with an alarm.

CIGARETTE-DENSE-END-MEASURING METHOD AND APPARATUS This is a continuation of my copending application Ser. No. 544,000, filed Apr. 20, I966.

The present invention relates generally to cigarette makers and, more particularly, to a method and means for facilitating the manufacture ofcigarettes having dense ends.

BACKGROUND Many cigarettes are being manufactured by providing extra tobacco in the tobacco rod at the regions which will form the adjacent ends of cut cigarettes. The purpose of this dense ending is to give the cigarette ends added firmness, good appearance and to prevent small particles of tobacco from falling out of loosely packed ends.

Dense-ending apparatuses are built into many modern cigarette machines and they may take on various forms. For example, suction techniques may be employed to drop increased amounts of tobacco onto the tobacco stream, compacting wheels may be used to compress the stream at various points or a rotating trimmer disc having peripheral indentations may be used to trim off more tobacco in some regions of the stream than in others. US. Pat. No. 3,032,041 issued to R. Lanore and British Patents 813,576, 940,153, 941,852, and 948,736 are representative of the state of the art in this area.

One problem that arises frequently with these systems is that the extra tobacco in the cigarette rod may occur at the wrong location. The cutter is normally synchronized with the dense-ending device so that the cutter cuts through the rod substantially in the center of the dense regions. While the system may be initially set up to provide cigarettes having suitable dense ends, the cutter may be located several feet downstream from the dense-ending device and the intervening rod forming mechanisms induce an unpredictable stretching of the tobacco stream and cigarette rod causing misregistration of the cutter with the dense regions. Instead of occurring in the two butted adjacent cigarette ends where the rod is cut, the dense regions may appear in the center of the cigarette.

Another problem concerns the amount of increased density added to the dense regions. Machines are commonly designed to put typically at percent, a percent, or a percent increase in density into the ends of the cigarettes. Machine faults or maladjustments may cause the magnitude of the dense regions of the tobacco rod to be less than desired.

PRIOR SYSTEMS It has been necessary to sample the density of a large number of cigarettes manually to determine whether or not the dense regions were of the desired magnitude and occurring at the ends of the cigarettes. When the production of faulty cigarettes was discovered, it was necessary to stop the machine and adjust the dense-ending device. This method was not only time consuming but also wasteful, as a large number of objectionable cigarettes were produced as a result of the high-production rate, e.g. 1,800 cigarettes per minute or more, by one machine, before the fault was discovered. Moreover, it was virtually impossible to discriminate between a loss of cutter synchronization and a decrease in density of the dense regions.

BRZEF DESCRIPTION OF THE PRESENT INVENTION I provide a system for determining when a machine is producing cigarettes having acceptable dense ends and a method for controlling it to maintain the desired cutter-dense end relationship. I use a gauge to provide a signal continuously proportional to the density or weight per unit length of the cigarette rod. A reference signal is obtained whenever the cutter cuts the cigarette rod. In one embodiment, I display the density signal simultaneously with the reference signal to indicate whether or not the cutter is synchronized and cutting through the dense regions. The machine may be adjusted to cut substantially through the center of each dense region to provide a continuous supply of dense end cigarettes. An improvement of this technique is the subject of a copending application Ser. No. 543,916 filed Apr. 20, 1966 by Alan Norwich and John Dewitt and assigned to the same assignee as the present application.

In another embodiment, I sample the density of the ends of the cigarette and adjust the machine to maximize the difference between the density at the ends and the density of the remainder of the cigarette. More specifically, I partition the density signal into two components: a first signal component represents the density of the segments of the tobacco rod which will form the ends of the cut cigarettes; the second signal component represents the density substantially of the remainder of the cigarette red. I compare the first component with the second component to determine when the dense regions are of the correct density and occurring in synchronism with the cutter. When, for example, the difference between the two signal components is the greatest, the dense regions of the rod are being separated by the cutter. l also provide an alarm system to warn operating personnel of faulty dense end production.

BRIEF DESCRIPTION OF THE OBJECTS Accordingly, it is a primary object of the present invention to provide a method and apparatus for continuously measuring and indicating the position of dense regions in a tobacco rod relative to the cutter in a cigarette-making machine.

It is also an object of the present invention to provide a dense-end-monitoring system that eliminates time-consuming manual sampling.

It is another object of the present invention to, provide a dense-end-monitoring system that responds not only to misregistration of the cutter but also to a deficient density condition with the further capability of being able to discriminate between these two causes of faulty dense ends.

It is still another object of the present invention to provide an improved method for controlling a cigarette machine to provide a continuous supply of dense end cigarettes.

BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a block diagram illustrating a cigarette-dense-endmachine-monitoring system, together with three associated graphs of typical waveforms depicting signal amplitudes as a function of time t;

FIG. 2 is a graph of cigarette rod density vs. time for two cigarette samples;

FIG. 3 is a plot of the magnitude of the output difference signal vs. phase angle between the cutter and the dense-ending mechanisms; and,

FIG. 4 is a diagrammatic view of one type of visual readout of dense end condition.

CIGARETTE DENSE END PROCESS With reference now to the drawings and particularly to FIG. 1, a cigarette making process includes a tobacco stream former it) delivering a stream 12 of tobacco to a rod former l4. Rod former l4 wraps a paper strip to around the tobacco stream l2 and glues the seam to form a cigarette rod 18. The cigarette rod is conveyed to a cutter 20 which periodically cuts a cigarette 22 of length L from the continuous rod 18. In the past, this type of industrial process has been measured and controlled to provide cigarettes having a desired weight per unit length. For a more detailed description of the cigarettemaking machine, reference may be had to US. Reissue Pat. Re. 25,476 issued Nov. 12, I963 to S. A. Radley et al. and assigned to the same assignee as the present invention.

Some machines are equipped with a dense end device 24 which may comprise a rotating trimmer disc having raised portions spaced around the periphery thereof. Other devices may be employed to provide the same function; some of these are described in the patents cited, supra. The disc trims off some tobacco 12a from the stream 12 to form a stream having dense regions R spaced one cigarette length L apart from one another. The density of the tobacco in the dense regions R of the trimmed stream or cigarette rod 18 may be up to 20 percent greater than the density in the remainder of the trimmed stream or the rod 18. In a typical example, the length AL of the dense region may be to mm. in length while the entire cigarette may be some 70 mm. in length.

A main drive motor 26 provides the motive power for simultaneously conveying the cigarette rod 18 toward the cutter 20 and actuating the cutter 20 to cut cigarettes of substantially equal length from the rod 18. The dense end device 24 is also coupled to the main drive motor 26 as indicated by the dotted line 28. The object is to time the cutter operation with the dense end device 24 so that the cutter 20 cuts the tobacco rod 18 substantially in the center of each dense region R. If, due to longitudinal dimensional changes of the rod 18 or slippage of the drive to either the cutter 20 or the dense end trimmer, the cutter and dense regions R are not in synchronism, the cigarettes 22 will either have an insufficient amount of tobacco at one end or the other or no dense ends at all.

This effect is graphically shown in FIG. 2 wherein a density profile 27 is plotted on the same time scale as pulses 29 occurring when the cutter 20 cuts through the tobacco rod. A superposed cigarette 22 is shown in section to illustrate an acceptable dense end condition (Case I) and an objectionable dense end condition (Case ll). In both cases, the location of the ends of the cigarettes 22 are in time coincidence with the cutter pulses 29. In Case I, however, the dense regions R arrive at the cutter 20 when a cigarette is being cut. Cigarettes are provided with dense end portions. Case ll illustrates a situation where the dense regions R arrive at the cutter 20 several milliseconds late so that the cut cigarettes contain a centrally located dense portion.

DESCRIPTION OF THE PRESENT INVENTION To provide cigarettes having ends of the desired density, I continuously monitor the density of the cigarette rod 18 and determine when the dense regions R appear at the cutter. A density gauge 30 such as a capacitance gauge or a nuclear radiation gauge is positioned preferably a short distance upstream and as near as physically possible to the cutter 20.

A pair of

gates

32 and 34 receive the output signal from the gauge 30 and route the signal alternately into two separate paths. During part of the time the signal is transmitted only along a first path through gate 32. During the remainder of the time the signal is transmitted only along a second path through gate 34. The operation of the gates is timed so that gate 32 transmits the time-selected component of the gauge signal with is responsive to the density of the cigarette rod 18 in the region where it is cut by the cutter 20. The timing is also such that gate 34 transmits the other component of the gauge signal which is responsive to the density of the cigarette rod in the central regions thereof between the cut ends of the cigarettes made from the rod.

The

gates

32 and 34 are controlled by pulse signals from a cutter pulse generator 36 coupled to the cutter 29 to generate a pulse train 38. Pulse train 38 includes pulses occurring as every cigarette 22 is cut. The on-time T of the pulse 38 may be of any duration, but it is preferably fixed in accordance with the time of transport of the typical length, AL, of each dense region past a given point such as the density gauge 30. The pulses 38 can be generated, for example, by cam-actuated limit switches or by a photocell receiving light reflected off a segmental reflecting portion of a rotating cutter axle or hub. The mechanical connection between the cutter pulse generator 36 and the cutter 20 is represented by the dotted line 40. Gate 32 is opened by the pulses in the cutter pulse train 33 for the time T,. Gate 34 is closed during this time. Gate 32 is closed for the time T and gate 34 is opened for this period. In a simple form,

gates

32 and 34 could comprise a single-pole double-throw switch actuated by the cutter mechanism in an arrangement similar to that illustrated and described in U.S. Pat. No. 2,357,860 issued Sept. 12, 1944 to U. A. Whitaker or in U.S. Pat. No. 2,999,520 issued Sept. I2, 1961 to W. B. Lowman.

it may be desirable to mount the density gauge 30 a known distance, such as an integral number of cigarette lengths, nL, away from the cutter 20 so that when one dense region is being measured by the gauge 30, a previous one is located at the cutter 20. in this case the delay unit 31 may be omitted, as indicated by the dotted line showing the same. In those cases where the gauge 30 introduces an inherent lag in measuring the density of the cigarette rod 18 that is large with respect to the time of transport of one cigarette length L past a given point, it may be necessary to delay the cutter signal for this period to insure that only those portions of the gauge signals representing the density of the segments of rod 18 destined to form the ends of the cigarettes 22 are selected for transmission by the gate 32. Alternatively, the gauge signal itself may be delayed by a delay unit 31 to insure the desired time correspondence of the periodic closing of gate 32. Since any one dense region R is ordinarily subdivided between one cigarette 22 and the next, the cutter pulse generator 36 is adjusted to provide cutter pulses 38 that start slightly in advance of each stroke of the cutter 20, so that the portion of the gauge signal passing through the gate 32 during a given opening thereof represents a cigarette rod portion including equal lengths of the trailing part of one cigarette and the leading part of the succeeding cigarette. When the various delays are accounted for, only the density of the ends of the cigarettes is being indicated by the portion of the density gauge signal transmitted by the gate 32.

The

gates

32 and 34 thus deliver signals S, and S having the waveforms shown. The signal S represents the variations in the density of that portion of the cigarette rod 18 including a part immediately before and a part immediately after the location where it is cut by the cutter 20. The density variations appear for only a relatively short period of time T, and are representative of that portion of the cigarette rod 18 which forms the butted ends of adjacent cigarettes. The signal S represents the variations in the density of the remaining central portion of each cigarette 22. The magnitude of signal S is generally smaller than the magnitude of signal S,.

The average value of signals S and S are computed by a pair of averaging

circuits

42 and 44. A difference computer 46 provides an output signal S the magnitude of which can be read out on a meter 48. The signal S is proportional to the difference between the averaged values of signals S and S OPERATION OF THE PRESENT lNVENTlON If the density gauge is spaced 2. distance nL upstream from the cutter, dense regions R will occur simultaneously at the density gauge 30 and at the cutter 20. If a dense region is detected by the gauge 3t) at the same time cutter 20 is cutting through the cigarette rod 18 the signal 8,, will be relatively large. The signal S being representative of the density of the central, less dense area of the cigarettes 22, will be less. The difference signal S reaches a maximum value graphically indicated in MG. 3 indicating exact synchronization of the cutter 2% with the dense-ending device 24.

Should the dense regions R of the cigarette rod 18 for one reason or another, leg or lead relative to the cutter 20, some of the measured increased density will appear in signal S increasing its average value. Similarly, the average value of signal S will decrease due to the decrease in measured density for the end segment portions of the cigarette rod 13. The result is a significant decrease in the difierence signal S Any change in the indication of meter 43 from maximum deflection may be indicative of a faulty dense end condition. Thus, according to the method of the present invention, operating personnel, by observing the face of meter 48, are immediately advised of any deterioration in machine performance so that suitable correction can be made to produce continuously cigarettes having acceptable dense ends.

The signal comparison technique provides a way to check the magnitude of the density of the dense regions against that of the remaining portion of the cigarettes. Therefore, if the average weight of the cigarettes falls below a specification or target weight, my system will still determine the relative magnitude difference and indicate when objectionable dense end cigarettes are being produced.

As mentioned above, a machine malfunction may result in a reduction in the density of the dense regions R. Such a reduction causes a decrease in the magnitude of signals S and S even though cutter synchronization is maintained. As a check, I provide a deviation analyzer that can be used to affirm or reject cutter synchronization as a cause of a downward deflection of the indication on meter 48.

DEVIATION ANALYZER Referring to FIG. 4, the density gauge 30 preferably comprises a radiation source 52 and a detector 54 positioned on opposite sides of the cigarette rod 18. The density functional signal derived by the detector 54 is transmitted to a visual indicator such as oscilloscope 56 along with the pulse train provided by a cutter pulse generator 36. Again, in some cases, it may be necessary to delay the density signal by means of a delay unit 59. The two signals may be displayed instead on a fast chart recorder such as is marketed by Honeywell, Inc., under the Trade Mark, VISICORDER, and described in US. Pat. No. 2,580,427. The two signals are separately coupled into vertical deflection channels A and B of the oscilloscope 56. The cutter pulses can be used to trigger the horizontal sweep of the oscilloscope. The result is a graphical display of a trace 60 representative of the density of the cigarette rod 18 in time coincidence with a trace 62 representative of the cutter pulses. Operating personnel are visually advised of the amount and direction of any deviation in cutter synchronization by observing the lateral shift in the cutter pulse relative to the dense end peaks in the density trace 60. When the cutter pulse is vertically aligned with the density peaks representative of the dense regions R, the cutter is fully synchronized. The amount of time lead or lag can be estimated from the distance between the dotted lines 66 for the purpose of controlling the process according to the method of the present invention, to maintain the desired cutter synchronization.

Instead of equipping each cigarette machine in a plant with an analyzer, I provide a simple alarm system on each machine to warn of a faulty dense end condition (see FIG. 1 An alarm 70 which may be a buuer or a flashing light is energized when a signal comparator 72, comparing the magnitude of the difference signal S with that of a reference signal from a generator 74, finds that the difference signal has dropped below the threshold shown in dotted lines in FIG. 3. The magnitude of the reference signal is selectable by a control knob 75, since the difference signal magnitude will depend on how much extra density a given machine is designed to put into the dense regions R of the cigarette rod 13.

An alarm indication may call for investigation of the machine by operating personnel. My deviation analyzer (FIG. 4) can be made portable and rolled up to the faulty machine in response to an alarm indication. As is well known, each cigarette machine is ordinarily equipped with a gauge 30, arranged so that a strip chart recorder or portable process analyzer can be temporarily plugged in via the usual jack, and a similar jack can be provided for the connection of the oscilloscope 56 and/or delay unit 59. Similarly, each machine may have the photocell detector or limit switch of the cutter pulse generator 36 permanently mounted and equipped with a suitable jack. Synchronization can then be quickly checked by routing the density gauge signal and the cutter pulses directly into the oscilloscope 56. If the cutter pulses of trace 62 line up with the dense end pulses of trace 60, it is at once apparent to the operator that the alarm indication was not caused by a lack of cutter synchronization, but was the result of some other mechanical malfunction such as would cause starving of the tobacco supply to the dense regions R.

ALTERNATIVE EMBODIMENTS While a dual density signal comparison circuit is shown and described, it has particular utility on lines where the average weights of the cigarettes wander from the desired specification on target value. If this is not the case, the magnitude of the signal S alone can be processed to determine whether or not the desired dense end condition is being maintained. The alternate signal channel does, however, also provide one with a source from which the average weight of cigarettes (minus the dense ends) can be readout.

My system also provides a method for controlling the cigarette-dense-ending process of FIG. 1. One may manually adjust the relative position of the dense end device 24 and the cutter 20 in response to a downward deflection of the indication of meter 48. This may be done by stopping the machine and rotating the trimmer disc slightly while maintaining the position of the cutter, by altering the spacing between the two units or by other means more suited to the type of machine being monitored. Alternatively, a differential gearing unit 76 (see FIG. 1) can be adjusted through a servo unit 78. The differential unit 76 may have a pair of output shafts 80 and 82, driven by the main drive motor 26 and having a speed ratio of adjustable magnitude. Shafts 80 and 82 may be coupled to the cutter 20 and the dense end device 24, respectively. Servo 78 can be coupled to the ratio adjusting member of the differential 76 as indicated by the heavy dotted line 84 and actuated from a remote location.

Alternatively, the differential 76 or other mechanical drive expedients can be manually adjusted by operating personnel observing the face of the oscilloscope 56 (FIG. 4). The advantage of this type of data readout over that provided by the meter 48 is that one can see immediately in which direction correction must be initiated to establish the desired synchronization.

Although certain specific embodiments of the invention have been shown and described herein, many modifications may be made thereto without departing from the true spirit and scope of the invention as set forth in the appended claims.

What is claimed is:

l. The method of monitoring the operation of a machine for producing cigarettes having dense ends, said machine having means for forming a continuous tobacco rod containing extra tobacco in locally dense regions uniformly spaced along its length and means for conveying said rod along a path including the location of a cutter for providing a plurality of cigarettes cut from said rod, said method comprising the steps of:

measuring the density of said rod as it passes a point along said path to produce a first signal having a recurrent dense region indicating signal portion responsive to said dense regions and another signal portion responsive to other regions in said tobacco rod,

generating a recurrent reference signal in response to the operation of said cutter, and

comparing the phase of said reference signal with the phase of one of said first signal portions to provide a quantitative indication of the distance along the rod between the position of said dense regions and the ends of the cut cigarettes.

2. The method of monitoring the operation of a machine for producing cigarettes having dense ends, said machine having means for forming a continuous tobacco rod having locally relatively dense regions uniformly spaced along its length and means for conveying said rod along a path including the location of a cutter for providing a plurality of cigarettes cut from said rod, said method comprising the steps of:

measuring the density ofsai fod affixed location along said path before the rod is cut by said cutter to produce a first signal having a recurrent dense region indicating signal portion responsive to the passage of said dense regions and another signal portion responsive to the passing of other regions in said tobacco rod,

delaying said first signal to provide a measure of the density of said tobacco rod occurring at said cutter when said rod is cut,

comparing the phase of said reference signal with the phase of one of said first signal portions in said delayed first signal to indicate the position of said dense regions rela tive to the ends of said out cigarettes.

3. The method of monitoring the operation of a cigarettemaking machine having a cutter providing a plurality of cigarettes from a continuous rod of tobacco moving relative to said cutter and having locally dense regions spaced along said tobacco rod, said method comprising the steps of:

continuously measuring the density of said tobacco rod occurring in advance of said cutter,

generating a signal whenever said cutter cuts through said tobacco rod, and

displaying said density measurement and said generated signal to visually determine the position along the rod of each of said locally dense regions relative to the ends of said cut cigarettes.

4. The method of monitoring the operation of a cigarettemaking machine having a cutter providing a plurality of cigarettes cut from a continuous rod moving relative to said cutter and having locally dense regions spaced along said cigarette rod by a dense end device, said method comprising the steps of:

continuously measuring the density of said cigarette rod,

partitioning said continuous density measurement into a first component representing the density of the segments of said cigarette rod which will form the ends of said cut cigarettes and a second component representing the density of the remainder of said cigarette rod, and

comparing said first density component with said seconddensity component to determine when said end segments include said locally dense regions.

5. The method of claim 4 which further includes the step of:

adjusting the relative position of said cutter and said dense end device to maximize the magnitude of said first density component so that each of said locally dense regions of said cigarette rod is included in the butted ends of two adjacent cigarettes.

6. The method of synchronizing the operation of the cutting mechanism and the denseend-forming means of a cigarettemaking machine providing a plurality of cigarettes cut from a continuous cigarette rod moving relative to said cutter mechanism and having locally dense regions spaced along said cigarette rod, said method comprising the steps of:

measuring the density of said cigarette rod before it is cut by said cutting mechanism,

selecting portions of said density measurement at time intervals synchronized with said cutting mechanism,

averaging said selected portions to obtain a first signal,

averaging other portions of said density measurement to obtain a second signal, comparing said first signal with said second signal to obtain a difference signal, and

producing an indication in response to said difference signal that said cutting mechanism is cutting said cigarette rod substantially in the center of each of said locally dense regions.

7. The method of synchronizing the operation of the cutting mechanism and the dense-end-forming means of a cigarettemaking machine providing a plurality of cigarettes from a continuous rod moving relative to said cutting mechanism and having locally dense regions substantially equally spaced along said cigarette rod by said dense end forming means, said method comprising the steps of:

measuring the density of said cigarette rod at an inspection station,

averaging said selected density measurement portions to obtain a first signal,

averaging the remaining portions of said density measurement occurring at other time intervalsto obtain a second signal, comparing said first signal with said second signal to obtain a difference signal, and

adjusting the relative positions of said cutting mechanism and said dense end former to maximize said difference signal and provide cigarettes having a portion of said locally dense regions located at each end of each of said cigarettes.

8. Apparatus for synchronizing a cutting mechanism and a dense-endforrning means in a cigarette-making machine providing a continuous traveling rod having locally dense regions spaced along the length thereof, said apparatus comprismg:

means for continuously measuring the density of said cigarette rod upstream from said cutter,

means for generating a signal having a pulse whenever said cutter cuts through said cigarette rod, and

means for receiving and simultaneously displaying said density measurement and said generated pulse to visually indicate the position of said locally dense regions relative to the ends of said cut cigarettes.

9. Apparatus for monitoring the operation of a cigarettemaking machine having a cutter providing a plurality of cigarettes cut from a continuous rod moving relative to said cutter and having locally dense regions spaced .along said tobacco rod, said apparatus comprising:

means for continuously measuring the density of said cigarette rod,

means for partitioning said continuous density measurement into a first component representing the density of the segments of said cigarette rod which will form the ends of said out cigarettes and a second component representing the density of another part of said cigarette rod, and

means for comparing said first density component with said second density component to determine when said end segments include said locally dense regions.

10. Apparatus for a cigarette-making machine providing a continuous traveling rod having locally dense regions spaced along the length thereof and including a cutter for cutting individual cigarettes from said traveling rod, said apparatus comprising:

means for measuring the average density of said cigarette rod in the regions thereof where the rod is to be cut by said cutter,

means for measuring the average density of other regions of said cigarette rod,

means for comparing said average density measurements to obtain a difference signal, and

means for utilizing said difference signal to indicate when said cutter is cutting substantially in the center of each of said locally dense regions. 11. Apparatus for a cigarette-making machine providing a continuous traveling rod having locally dense regions spaced along the length thereof and including a cutter for cutting individual cigarettes from said traveling rod, said apparatus comprising:

means for continuously measuring the density of said continuous cigarette rod in the vicinity of said cutter mechanism and developing a signal in response thereto,

means for generating a signal having a pulse substantially at the same time said cutter passes through said cigarette rod, and

means for graphically displaying said density signal and said cutter pulse signal simultaneously to determine the phase relationship between said cutter operation and the occurrence of said locally dense regions of said cigarette rod at said cutter. 12. Apparatus for synchronizing the operation of the cutter of the knife mechanism of a cigarette-making machine and a dense end former providing a plurality of cigarettes cut from a continuous traveling rod having locally dense regions spaced along said rod by said rotating dense end former, said apparatus comprising:

a radiation gauge for measuring the density of the rod and for providing an output signal proportional thereto in the vicinity of said cutter, gate means actuated by said knife mechanism for partitioning said output signal including a first gate passing for a fixed period of time a portion of said output signal representative of the density of said cigarette rod in the vicinity of said cutter and a second gate passing the remaining portion of said radiation gauge output signal,

signal-averaging means for averaging the value of each of said signals passed by said first and second gate,

means providing a third signal proportional to the difference between said averaged gate signals, and

means responsive to said third signal for indicating the position of said locally dense regions relative to the ends of said out cigarettes.

13. Apparatus as set forth in claim 12, in which said means responsive to said third signal includes:

an alarm, and

means for energizing said alarm whenever the magnitude of said difference signal falls below a predetermined minimum level.

14. Apparatus for monitoring the operation of a machine for producing cigarettes having dense ends, said machine having means for forming a continuous tobacco rod having locally relatively dense regions uniformly spaced along its length and means for conveying said rod along a path including the location of a cutter for providing a plurality of cigarettes cut from said rod, said apparatus comprising:

means for measuring the density of said rod as it passes a point along said path to produce a first signal having a recurrent dense region indicating signal portion responsive to said dense regions and another signal portion responsive to other regions in said tobacco rod,

means for generating a recurrent reference signal in response to the operation of said cutter, and

means for comparing the phase of said reference signal with the phase of one of said first signal portions to provide a quantitative indication of the distance between the position of said dense regions and the ends of the cigarettes.

15. A method for controlling a machine for producing cigarettes having dense ends, said machine having means including a dense end device for forming a continuous tobacco rod having locally relatively dense regions uniformly spaced along its length and means for conveying said rod along a path including the location of a cutter for providing a plurality of cigarettes cut from said rod, comprising the steps of:

generating a recurrent reference signal in response to the operation of said cutter, and '4 adjusting the relative speed of operation of said dense end device and said cutter in response to the relative phases of said reference signal and one of said first signal portions. 16. Apparatus for monitoring the operation of a cigarettemaking machine having a cutter providing a plurality of cigarettes cut from a continuous rod of tobacco moving relative to said cutter and having locally dense regions spaced along said tobacco rod by a dense end device, said apparatus comprising:

means responsive to the density of said tobacco rod as it moves toward said cutter for producing a signal having a dense region indicating signal portion responsive to said dense regions and another signal portion responsive to other regions in said tobacco rod,

means for measuring the phase relationship between the operation of said cutter to out said rod and the occurrence of said dense region indicating signal portions to provide a signal which is a function of the deviation of the position of said dense regions from the ends of said cut cigarettes.

17. Apparatus for monitoring the operation of a cigarettemaking machine having a cutter providing a plurality of cigarettes cut from a continuous rod moving relative to said cutter and having locally dense regions spaced along said tobacco rod by a dense end device, said apparatus comprising:

means for generating a first signal whenever one of said dense regions should occur at said cutter,

means for generating a second signal whenever said cutter cuts a cigarette from said rod, and

means for continuously comparing the phase of said first signal relative to said second signal to determine the relative degree of synchronization between said cutter and said dense regions occurring thereat.

18. Apparatus for monitoring the operation of a cigarettemaking machine having a cutter providing a plurality of cigarettes cut from a continuous rod of tobacco moving relative to said cutter and having locally dense regions spaced along said tobacco rod by a dense end device, said apparatus comprising:

means for continuously measuring the density of said cigarette rod to provide a signal having a periodic increased portions corresponding to said dense regions of said rod as they should occur at said cutter,

means coupled to said cutter to provide a reference pulse whenever a cigarette is cut from said cigarette rod,

phase detector means for measuring a phase difference of said measured increased density portions from said reference pulses, and

means for utilizing said measured phase difference to indicate a deviation of said dense regions from the ends of said out cigarettes.

19. Apparatus for monitoring the operation of a cigarettemaking machine having a cutter providing a plurality of cigarettes cut from a continuous rod of tobacco moving relative to said cutter and having locally dense regions spaced along said rod, said apparatus comprising:

means for continuously measuring the density of said tobacco rod to produce a density signal,

means responsive to the operation of said cutter as it cuts said rod for producing a second signal, and

means for displaying said measured density signal and said second signal to indicate the position of said dense regions relative to the ends of said cigarettes.

Claims

1. The method of monitoring the operation of a machine for producing cigarettes having dense ends, said machine having means for forming a continuous tobacco rod containing extra tobacco in locally dense regions uniformly spaced along its length and means for conveying said rod along a path including the location of a cutter for providing a plurality of cigarettes cut from said rod, said method comprising the steps of: measuring the density of said rod as it passes a point along said path to produce a first signal having a recurrent dense region indicating signal portion responsive to said dense regions and another signal portion responsive to other regions in said tobacco rod, generating a recurrent reference signal in response to the operation of said cutter, and comparing the phase of said reference signal with the phase of one of said first signal portions to provide a quantitative indication of the distance along the rod between the position of said dense regions and the ends of the cut cigarettes.

2. The method of monitoring the operation of a machine for producing cigarettes having dense ends, said machine having means for forming a continuous tobacco rod having locally relatively dense regions uniformly spaced along its length and means for conveying said rod along a path including the location of a cutter for providing a plurality of cigarettes cut from said rod, said method comprising the steps of: measuring the density of said rod at fixed location along said path before the rod is cut by said cutter to produce a first signal having a recurrent dense region indicating signal portion responsive to the passage of said dense regions and another signal portion responsive to the passing of other regions in said tobacco rod, delaying said first signal to provide a measure of the density of said tobacco rod occurring at said cutter when said rod is cut, generating a recurrent reference signal in response to the operation of said cutter, and comparing the phase of said reference signal with the phase of one of said first signal portions in said delayed first signal to indicate the position of said dense regions relative to the ends of said cut cigarettes.

3. The method of monitoring the operation of a cigarette-making machine having a cutter providing a plurality of cigarettes from a continuous rod of tobacco moving relative to said cutter and having locally dense regions spaced along said tobacco rod, said method comprising the steps of: continuously measuring the density of said tobacco rod occurring in advance of said cutter, generating a signal whenever said cutter cuts through said tobacco rod, and displaying said density measurement and said generated signal to visually determine the position along the rod of each of said locally dense regions relative to the ends of said cut ciGarettes.

4. The method of monitoring the operation of a cigarette-making machine having a cutter providing a plurality of cigarettes cut from a continuous rod moving relative to said cutter and having locally dense regions spaced along said cigarette rod by a dense end device, said method comprising the steps of: continuously measuring the density of said cigarette rod, partitioning said continuous density measurement into a first component representing the density of the segments of said cigarette rod which will form the ends of said cut cigarettes and a second component representing the density of the remainder of said cigarette rod, and comparing said first density component with said second density component to determine when said end segments include said locally dense regions.

5. The method of claim 4 which further includes the step of: adjusting the relative position of said cutter and said dense end device to maximize the magnitude of said first density component so that each of said locally dense regions of said cigarette rod is included in the butted ends of two adjacent cigarettes.

6. The method of synchronizing the operation of the cutting mechanism and the dense-end-forming means of a cigarette-making machine providing a plurality of cigarettes cut from a continuous cigarette rod moving relative to said cutter mechanism and having locally dense regions spaced along said cigarette rod, said method comprising the steps of: measuring the density of said cigarette rod before it is cut by said cutting mechanism, selecting portions of said density measurement at time intervals synchronized with said cutting mechanism, averaging said selected portions to obtain a first signal, averaging other portions of said density measurement to obtain a second signal, comparing said first signal with said second signal to obtain a difference signal, and producing an indication in response to said difference signal that said cutting mechanism is cutting said cigarette rod substantially in the center of each of said locally dense regions.

7. The method of synchronizing the operation of the cutting mechanism and the dense-end-forming means of a cigarette-making machine providing a plurality of cigarettes from a continuous rod moving relative to said cutting mechanism and having locally dense regions substantially equally spaced along said cigarette rod by said dense end forming means, said method comprising the steps of: measuring the density of said cigarette rod at an inspection station, selecting portions of said density measurement at time intervals synchronized with said cutting mechanism, averaging said selected density measurement portions to obtain a first signal, averaging the remaining portions of said density measurement occurring at other time intervals to obtain a second signal, comparing said first signal with said second signal to obtain a difference signal, and adjusting the relative positions of said cutting mechanism and said dense end former to maximize said difference signal and provide cigarettes having a portion of said locally dense regions located at each end of each of said cigarettes.

8. Apparatus for synchronizing a cutting mechanism and a dense-end-forming means in a cigarette-making machine providing a continuous traveling rod having locally dense regions spaced along the length thereof, said apparatus comprising: means for continuously measuring the density of said cigarette rod upstream from said cutter, means for generating a signal having a pulse whenever said cutter cuts through said cigarette rod, and means for receiving and simultaneously displaying said density measurement and said generated pulse to visually indicate the position of said locally dense regions relative to the ends of said cut cigarettes.

9. Apparatus for monitoring the operation of a cigarette-making machine having a cutter providing a plurality of cigarettes cut from a continuous rod moving relative to said cutter and having locally dense regions spaced along said tobacco rod, said apparatus comprising: means for continuously measuring the density of said cigarette rod, means for partitioning said continuous density measurement into a first component representing the density of the segments of said cigarette rod which will form the ends of said cut cigarettes and a second component representing the density of another part of said cigarette rod, and means for comparing said first density component with said second density component to determine when said end segments include said locally dense regions.

10. Apparatus for a cigarette-making machine providing a continuous traveling rod having locally dense regions spaced along the length thereof and including a cutter for cutting individual cigarettes from said traveling rod, said apparatus comprising: means for measuring the average density of said cigarette rod in the regions thereof where the rod is to be cut by said cutter, means for measuring the average density of other regions of said cigarette rod, means for comparing said average density measurements to obtain a difference signal, and means for utilizing said difference signal to indicate when said cutter is cutting substantially in the center of each of said locally dense regions.

11. Apparatus for a cigarette-making machine providing a continuous traveling rod having locally dense regions spaced along the length thereof and including a cutter for cutting individual cigarettes from said traveling rod, said apparatus comprising: means for continuously measuring the density of said continuous cigarette rod in the vicinity of said cutter mechanism and developing a signal in response thereto, means for generating a signal having a pulse substantially at the same time said cutter passes through said cigarette rod, and means for graphically displaying said density signal and said cutter pulse signal simultaneously to determine the phase relationship between said cutter operation and the occurrence of said locally dense regions of said cigarette rod at said cutter.

12. Apparatus for synchronizing the operation of the cutter of the knife mechanism of a cigarette-making machine and a dense end former providing a plurality of cigarettes cut from a continuous traveling rod having locally dense regions spaced along said rod by said rotating dense end former, said apparatus comprising: a radiation gauge for measuring the density of the rod and for providing an output signal proportional thereto in the vicinity of said cutter, gate means actuated by said knife mechanism for partitioning said output signal including a first gate passing for a fixed period of time a portion of said output signal representative of the density of said cigarette rod in the vicinity of said cutter and a second gate passing the remaining portion of said radiation gauge output signal, signal-averaging means for averaging the value of each of said signals passed by said first and second gate, means providing a third signal proportional to the difference between said averaged gate signals, and means responsive to said third signal for indicating the position of said locally dense regions relative to the ends of said cut cigarettes.

13. Apparatus as set forth in claim 12, in which said means responsive to said third signal includes: an alarm, and means for energizing said alarm whenever the magnitude of said difference signal falls below a predetermined minimum level.

14. Apparatus for monitoring the operation of a machine for producing cigarettes having dense ends, said machine having means for forming a continuous tobacco rod having locally relatively dense regions uniformly spaced along its length and means for conveying said rod along a path including the location of a cutter for providing a plurality of cigarettes cut from said rod, said apparatus compriSing: means for measuring the density of said rod as it passes a point along said path to produce a first signal having a recurrent dense region indicating signal portion responsive to said dense regions and another signal portion responsive to other regions in said tobacco rod, means for generating a recurrent reference signal in response to the operation of said cutter, and means for comparing the phase of said reference signal with the phase of one of said first signal portions to provide a quantitative indication of the distance between the position of said dense regions and the ends of the cigarettes.

15. A method for controlling a machine for producing cigarettes having dense ends, said machine having means including a dense end device for forming a continuous tobacco rod having locally relatively dense regions uniformly spaced along its length and means for conveying said rod along a path including the location of a cutter for providing a plurality of cigarettes cut from said rod, comprising the steps of: measuring the density of said rod as it passes a point along said path to produce a first signal having a recurrent dense region indicating signal portion responsive to said dense regions and another signal portion responsive to other regions in said tobacco rod, generating a recurrent reference signal in response to the operation of said cutter, and adjusting the relative speed of operation of said dense end device and said cutter in response to the relative phases of said reference signal and one of said first signal portions.

16. Apparatus for monitoring the operation of a cigarette-making machine having a cutter providing a plurality of cigarettes cut from a continuous rod of tobacco moving relative to said cutter and having locally dense regions spaced along said tobacco rod by a dense end device, said apparatus comprising: means responsive to the density of said tobacco rod as it moves toward said cutter for producing a signal having a dense region indicating signal portion responsive to said dense regions and another signal portion responsive to other regions in said tobacco rod, means for measuring the phase relationship between the operation of said cutter to cut said rod and the occurrence of said dense region indicating signal portions to provide a signal which is a function of the deviation of the position of said dense regions from the ends of said cut cigarettes.

17. Apparatus for monitoring the operation of a cigarette-making machine having a cutter providing a plurality of cigarettes cut from a continuous rod moving relative to said cutter and having locally dense regions spaced along said tobacco rod by a dense end device, said apparatus comprising: means for generating a first signal whenever one of said dense regions should occur at said cutter, means for generating a second signal whenever said cutter cuts a cigarette from said rod, and means for continuously comparing the phase of said first signal relative to said second signal to determine the relative degree of synchronization between said cutter and said dense regions occurring thereat.

18. Apparatus for monitoring the operation of a cigarette-making machine having a cutter providing a plurality of cigarettes cut from a continuous rod of tobacco moving relative to said cutter and having locally dense regions spaced along said tobacco rod by a dense end device, said apparatus comprising: means for continuously measuring the density of said cigarette rod to provide a signal having a periodic increased portions corresponding to said dense regions of said rod as they should occur at said cutter, means coupled to said cutter to provide a reference pulse whenever a cigarette is cut from said cigarette rod, phase detector means for measuring a phase difference of said measured increased density portions from said reference pulses, and means for utilizing said measured phase difference to indicate a deviation of saId dense regions from the ends of said cut cigarettes.

19. Apparatus for monitoring the operation of a cigarette-making machine having a cutter providing a plurality of cigarettes cut from a continuous rod of tobacco moving relative to said cutter and having locally dense regions spaced along said rod, said apparatus comprising: means for continuously measuring the density of said tobacco rod to produce a density signal, means responsive to the operation of said cutter as it cuts said rod for producing a second signal, and means for displaying said measured density signal and said second signal to indicate the position of said dense regions relative to the ends of said cigarettes.