US3825152A

US3825152A - Method and apparatus for measuring the rate of feed of fibrous material

Info

Publication number: US3825152A
Application number: US00272630A
Authority: US
Inventors: W Rudszinat; H Davis
Original assignee: Hauni Werke Koerber and Co KG
Current assignee: Koerber AG
Priority date: 1971-07-20
Filing date: 1972-07-17
Publication date: 1974-07-23
Anticipated expiration: 1991-07-23
Also published as: FR2146793A5; GB1397929A; DE2226261A1

Abstract

A distributor for tobacco shreds in a cigarette rod making machine employs a system of conveyors which transport a continuous wide layer of tobacco shreds from a magazine toward a channel wherein the shreds form a narrow tobacco stream. A pivotable baffle extends across the path of the layer and a rotary brush or a rapidly moving endless apron propels the shreds of successive increments of the layer at a constant speed against the baffle whereby a potentiometer whose sliding contact shares the movement of the baffle produces signals whose intensity varies as a function of changes in the quantity of shreds per unit length of the layer. The thus obtained signals are used to change the rate of withdrawal of tobacco shreds from the magazine or to intercept a larger or smaller percentage of shreds which are being propelled toward the baffle. The main prime mover of the cigarette rod making machine can be operated at several speeds, and a compensating circuit is provided to prevent the potentiometer from changing the rate of tobacoo feed into the channel in response to changes in operating speed of the prime mover.

Description

United States Patent [1 1 Davis et al.

[451 July 23, 1974 [75] inventors: Harry Davis, Hamburg; Willy Rudszlnat, Dassendorf, both of Germany [73] Assignee: Hauni-Werke Koerber 8L Co. KG,

Hamburg, Germany [22] Filed: July 17, 1972 [21] Appl. No.: 272,630

[30] Foreign Application Priority Data July 20, 1971 Great Britain 34043/71 Nov. 9, 1971 Great Britain 51993/71 [52] US. Cl 222/1, 19/240, 222/55, 222/254 [51] Int. Cl. G0" 1/00 [58] Field of Search 222/1, 55, 56, 59, 71, 222/254; 198/37, 39, 40', 73/228; 19/240; 131/108, 109

{56] References Cited UNITED STATES PATENTS 2,737,997 3/1956 Himmelheber et al. 222/56 X 2,822,024 2/1958 Himmelheber et al. 222/55 X 2,872,074 2/1959 Birtwell et al. 222/55 3,631,961 1/1972 Strydom 198/37 3,640,136 2/1972 Nolte 73/228 FOREIGN PATENTS OR APPLICATIONS 602,283 12/1934 Germany Primary Examiner-Robert B. Reeves Assistant ExaminerFrancis .1. Bartuska Attorney, Agent, or FirmMichael S. Striker (57] ABSTRACT A distributor for tobacco shreds in a cigarette rod making machine employs a system of conveyors which transport a continuous wide layer of tobacco shreds from a magazine toward a channel wherein the shreds form a narrow tobacco stream. A pivotable baffle extends across the path of the layer and a rotary brush or a rapidly moving endless apron propels the shreds of successive increments of the layer at a constant speed against the baffle whereby a potentiometer whose sliding contact shares the movement of the baffle produces signals whose intensity varies as a function of changes in the quantity of shreds per unit length of the layer. The thus obtained signals are used to change the rate of withdrawal of tobacco shreds from the magazine or to intercept a larger or smaller percentage of shreds which are being propelled toward the baffle. The main prime mover of the cigarette rod making machine can be operated at several speeds, and a compensating circuit is provided to prevent the potentiometer from changing the rate of tobacco feed into the channel in response to changes in operating speed of the prime mover.

19 Claims, 8 Drawing Figures mamma 3.825.152

, SHE! 3 0f 5 METHOD AND APPARATUS FOR MEASURING THE RATE OF FEED OF FIBROUS MATERIAL BACKGROUND OF THE INVENTION The present invention relates to a method and apparatus for controlled transport of particles of fibrous material, especially particles of tobacco leaves and filter material. More particularly, the invention relates to a novel method and apparatus for measuring the rate of feed of fibrous particles which form a continuous layer and for regulating the rate of feed in response to such measurement. The apparatus of the present invention may constitute the distributor of a tobacco rod making or filter rod making machine wherein a continuous stream of fibrous material is wrapped into cigarette paper or other stripor web-shaped material to form therewith a continuous rod which is ready to be subdivided into plain cigarettes, cigars, cigarillos or filter rod sections of desired length.

The distributor of a cigarette, cigar or cigarillo rod making machine normally comprises a magazine which stores tobacco in the form of relatively large particles for the making of cigars or cigarillos, or in the form of narrow shreds which are used for the manufacture of cigarettes. The homogeneousness of the rod-like filler which is being wrapped in such machines to form a continuous wrapped tobacco rod depends to a large extent on the uniformity of the rate at which the particles are being fed into a customary channel to form therein a stream which is thereupon trimmed or equalized, compacted and/or otherwise treated to be converted into a filler rod. For the sake of simplicity, the following description of our invention will refer to distributors for use in cigarette rod making machine with the understanding, however, that such distributors can be used with equal advantage for the formation of streams which can be converted into fillers of cigars, cigarillos or filter rod sections.

Attempts to enhance the homogeneousness of fibrous material which is being fed into the stream forming channel include the provision of various loosening and propelling devices which serve to separate the normally interlaced shreds and to facilitate the formation of a relatively wide carpet or sliver the leading end of which is thereupon showered into the channel to be converted into a continuous stream. It was found that such devices are not entirely satisfactory, mainly because they cannot insure that each unit length of the carpet which is being showered into the channel contains the same quantity of shreds. This is attributable to differences in the quality of particles which form the carpet, such as fluctuations in the ratio of ribs or stem to comminuted tobacco leaf laminae, fluctuations in the ratio of short shreds to long shreds, fluctuations in proportions of different types of tobacco (such as Virginia, Burley, Oriental and others), fluctuations in the quantity of tobacco shreds in the magazine from which the conveyor system of the distributor draws or receives a continuous body of tobacco shreds, and many other factors. Fluctuations in the quantity of tobacco shreds in the magazine (wherein the supply of shreds is normally replenished from time to time) can influence the quantity of tobacco particles in the withdrawn layer of tobacco shreds to a considerable extent.

German Pat. No. 602,283 discloses a proposal to measure the weight of cigarettes by propelling successive cigarettes against a yieldably mounted baffle and by measuring the magnitude of forces which are being transmitted to the baffle by successive cigarettes. Such mode of measuring the weight of cigarettes is unreliable, mainly because the magnitude of force which is being transmitted by a rapidly propelled cigarette depends on the direction and distribution of shreds in its wrapper. Thus, two cigarettes having identical weights are likely to transmit different forces if the distribution and/or orientation of shreds in one cigarette is substantially different from the distribution and/or orientation of shreds in the other cigarette.

It was further proposed to utilize such measuring method for controlling the operation of the distributor in a cigarette machine by causing the particles of a continuously moving body of tobacco to impinge upon a baffle and by measuring the magnitude of forces which are being transmitted to the baffle. The results were unsatisfactory and, therefore, such attempts were given up more than five decades ago because the measurement was unreliable and could not be utilized to insure proper regulation of the rate of tobacco feed into the channel. This is attributable mainly to the fact that the particles were propelled against the baffle at different speeds and because the particles were allowed to re main interlaced or interlinked with each other. More over, the previously conducted experiments were unsatisfactory whenever the speed of tobacco transport was changed on purpose, for example, during acceleration of the cigarette rod making machine from a slower starting speed to the normal or full operating speed.

SUMMARY OF THE INVENTION An object of the invention is to provide a novel and improved method of accurately determining the rate of feed of fibrous particles which form a continuously moving body, such as a layer, sliver, carpet or the like.

Another object of the invention is to provide a novel and improved method of regulating the rate of transport or feed of fibrous material, particularly in the distributor of a tobacco rod making or filter rod making machine.

A further object of the invention is to provide a novel and improved method of automatically compensating for undesirable fluctuations in the rate of transport of feed of fibrous particles from a magazine into a channel wherein the particles are cuased to form a stream which is ready for wrapping into cigarette paper or the like.

An additional object of the invention is to provide an automatic method of manipulaing fibrous material in the distributor of a tobacco rod making or filter rod making machine in such a way that each unit length of the ultimate product (e.g., a narrow tobacco stream) contains identical quantities of fibrous particles so that such product can be wrapped and/or otherwise processed without any trimming or with negligible trim ming prior to the wrapping step.

Still another object of the invetion is to provide a novel and improved apparatus for determining the rate of feed of fibrous particles in a distributor for use in cigarette rod making or analogous machines and to provide the apparatus with novel and improved means for regulating the rate of feed when such rate deviates from a desired rate.

Another object of the invention is to provide the apparatus with novel and improved means for loosening fibrous material prior to determination of the quantity of such material per unit length of the body which is being transported from a main source to a processing station, such as the stream forming channel of a cigarette rod making machine.

An ancillary object of the invention is to provide the apparatus with novel means which compensates for eventual differnces in the size, weight, configuration and/or other characteristics of fibrous material and which is capable of automatically insuring that the continuously moving body of fibrous material invariably contains the same quantity of particles not later than when the body is to be subjected to a further treatment, such as conversion into a stream, wrapping into a continuous web of cigarette paper or the like.

The method of the present invention is used to determine the rate of transport or feed of fibrous particles which form a continuous body of moving particles. At the present time, the method is preferably utilized to determine the rate of feed of tobacco shreds or fibrous filter material in the distributor of a cigarette rod making machine or a filter rod making machine. The method comprises the steps of accumulating and maintaining in a suitable magazine a supply of fibrous particles, withdrawing from the supply a continuous body of fibrous particles at a varying rate by a system of conveyors and transporting the thus withdrawn particles along a predetermined path, imparting to the particles of successive increments of the body a predetermined constant speed while the particles travel in a predetermined portion of their path, establishing a barrier (e.g., a pivotable baffle) across the predetermined portion of the path so that the particles which move at the constant speed impinge against the barrier with a force which is proportional to the quantity of particles per unit length of the body, and measuring the force. The rate of withdrawal of fibrous particles from the supply normally varies at random, i.e., such rate normally fiuctuates within a certain range, or the fluctuation may be due to segregation of less satisfactory particles (such as tobacco ribs or stem) from satisfactory particles (such as shredded tobacco leaf laminae).

The measuring step may comprise producing a signal which is indicative of the quantity of fibrous particles per unit length of the body. The method may further comprise the step of utilizing such signal to regulate the rate of transport of fibrous particles into the predetermined portion of the path and preferably to regulate the rate of withdrawal of fibrous particles from the main supply.

If the rate of withdraw] of fibrous particles from the main supply is changed on purpose (for example, because the main prime mover of the cigarette rod making machine is caused to operate at the lower or higher of two speeds), the method preferably further comprises the step of automatically compensating for the resulting change in the intensity of the signal. The body of fibrous particles is preferably caused to assume the form of a carpet, sliver or layer whose height is only a small fraction of its width, especially in the predetermined portion of the path.

The aforementioned signal can be utilized to remove from the body of fibrous particles varying quantities of particles so that the quantity of removed particles respectively increases and decreases when the quantity of particles per unit length of the body respectively exceeds and is below a predetermined quantity. The removing step can be carried out by resorting to an intercepting device which intercepts a larger or smaller portion of a preferably carpet-shaped body. Such interception preferably takes place in the predetermined portion of the path. The step of imparting to the particles a constant speed may comprise propelling the particles against the barrier while the particles are in unsupported condition (for example, by being propelled in air), and the removing step preferably comprises intercepting varying quantities of unsupported fibrous parti cles.

The method may further comprise the step of accelerating the fibrous particles in a second portion of the path which is located downstream of the first mentioned portion, and converting the accelerated particles into a continuous narrow stream whose width need not exceed (or need not appreciably exceed) its height. The accelerating step may comprise subjecting fibrous particles to the mechanical accelerating action of a rapidly rotating brush or to the mechanical accelerating action of a rapidly moving conveyor belt. The accelerating step may further include or is accompanied by conversion of fibrous particles into a divergent shower which can be caused to accumulate on a narrow belt for transport into the wrapping mechanism of a cigarette rod making or filter rod making machine. The accelerating step is often desirable due to the fact that the impingement of particles against the barrier results in substantial deceleration of such particles since the kinetic energy of the particles is absorbed by the barrier.

The generation of signals can be effected by resorting to a potentiometer whose sliding contact is connected with the barrier and by mounting the barrier in such a way that it can yield to the force of fibrous particles to an extent which is a function of the combined quantity of particles per unit length of the body.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved apparatus itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic elevational view of a cigarette rod making machine including a distributor which embodies one form of the improved measuring apparatus;

FIG. 2 is an enlarged vertical sectional view of the distributor substantially as seen in the direction of arrows from the line IIII of FIG. 1;

FIG. 3 is an enlarged view of a detail in a distributor which constitutes a modification of the distributor shown in FIG. 2;

FIG. 4 is a horizontal sectional view as seen in the direction of arrows from the line IV-IV of FIG. 3;

FIG. 5 illustrates a portion of a distributor which con stitutes a modification of the distributor shown in FIGS. 3-4;

FIG. 6 illustrates a further distributor in a sectional view similar to that of FIG. 2;

FIG. 7 is an enlarged view of a detail in the distribu tor of FIG. 6, substantially as seen in the direction of arrow B in FIG. 6; and

FIG. 8 is a fragmentary sectional view of a further distributor constituting a modification of the distributor shown in FIGS. 6 and 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates a cigarette rod making machine of the type known Garanf and produced by Hauni Werke, Kr'irber & Co. K.G., of Hamburg-Bergedorf, Western Germany. The machine includes a distributor the details of which are shown in FIG. 2 and which serves to supply a continuous shower of tobacco shreds into an elongated narrow channel 1 wherein the shreds descend onto the upper stretch of an endless narrow foraminous belt 2 travelling along the upper side of an elongated air-permeable plate 3 constituting the top wall of a suction chamber 4. The purpose of the chamber 4 is to attract the descending tobacco shreds to the upper stretch of the moving belt 2 whereon the shreds form a growing narrow tobacco stream (see the stream forming zone C) moving in a direction to the right, as viewed in FIG. 1, and being transferred into the endless peripheral groove of a revolving suction wheel 6 which is driven to rotate in a counterclockwise direction. The peripheral groove of the suction wheel 6 extends along the outer side of an endless foraminous bottom wall which, in turn, surrounds a stationary suction chamber so that the narrow tobacco stream is attracted to the endless bottom wall during travel from the transfer station between the belt 2 and wheel 6 and at least to an equalizing station which accommodates a suitable trimming device 8 serving to remove the surplus of tobacco shreds to thus convert the narrow stream into a filler rod 9. The filler rod 9 is expelled from the peripheral groove of the suction wheel 6 by a tongue 11 and travels with the lower stretch of a foraminous endless transfer belt 12. The lower stretch of the belt 12 travels below the open underside of a suction chamber 12a which causes the filler rod 9 to adhere to the belt 12 and to thereupon enter a wrapping mechanism including an endless tape 17, a draping device 18, a paster l9 and a plate-like sealer 21.

The frame of the cigarette rod making machine supports a spindle for a roll I4 of expiring cigarette paper web 13 which passes through a splicing device 113, thereupon through an imprinting device 16 and onto the upper side of the upper stretch of tape 17 in the wrapping mechanism so that the filler rod 9 travels in the wrapping mechanism with and at the same speed as the web 13. The device 18 of the wrapping mechanism drapes the web 13 around the filler rod 9 whereby one marginal portion of the draped web 13 travels along and receives a film of adhesive from the paster 19. Such marginal portion is thereupon folded over the other marginal portion to form a customary seam which is heated by the plate-like sealer 21 to insure rapid setting of the adhesive film and to thus convert the filler rod 9 and web I3 into a wrapped cigarette rod 22.

The wrapped rod 22 is caused to move lengthwise into a customary cutoff 23 wherein a revolving or orbiting knife (not shown) severs the rod 22 at regular intervals to form a single tile of plain cigarettes of unit length or multiple unit length. Successive plain cigarettes are accelerated by a conventional kicker 24 which propels them into successive flutes of a rotary drum-shaped transfer conveyor 26. The latter converts the single tile of plain cigarettes into one or more rows of parallel cigarettes which travel sideways, either into a conventional tray filling device or directly into a filter cigarette making machine, not shown.

The purpose of the device 16 is to imprint on longitudinally spaced portions of the web 13 suitable indicia, such as the brand of the cigarette, the trademark of the manufacturer and/or other information. The reference character 27 denotes the main prime mover for the moving parts of the cigarette rod making machine. This prime mover is preferably a variablespeed electric motor and serves to drive the belt 2, wheel 6, belt 12, imprinting device 16, tape 17, cutoff 23 and conveyor The frame of the cigarette rod making machine further supports a fresh reel 14a of cigarette paper web 13a. The leader of the web is placed into the splicing device 113 and is automatically or semiautomatically spliced to the trailing end of the expiring web 13 when the supply 14 of expiring web is about to be exhausted.

FIG. 2 illustrates an improved gravity type distributor which is used in the cigarette rod making machine of FIG. 1 to supply a continous shower of loose tobacco shreds into the stream forming zone C. The distributor comprises a tobacco transporting system including an endless conveyor 31 here shown as a belt which is provided with carding 31a and is trained over rollers 32, 33 and 34. That stretch of the belt 31 which travels upwardly from the roller 32 toward the roller 33 constitutes a moving side wall of a magazine 36 which contains a main supply of interlaced and randomly distributed lighter and heavier tobacco shreds. The magazine 36 further comprises a stationary side wall 37 and two end walls, not shown. The roller 32 is driven in a counterclockwise direction (arrow 38) to advance the belt 31 in the direction indicated by arrow 39. The aforementioned upwardly moving stretch of the belt 31 withdraws from the main supply in the magazine 36 a continuous body or layer 41a of tobacco shreds. The width of this layer greatly exceeds its height and the height of the layer 410 is determined by an adjustable equalizing device 52 here shown as a rotor having preferably elastic blades which return the surplus of shreds into the magazine 36. The equalizing device 52 rotates in the direction indicated by arrow SI.

Those stretches of the belt 31 which extend between the rollers 32, 33, and 33, 34 define for the shreds of the tobacco layer 41a an elongated path which extends along a first or removing station A and a second or collecting station B. The station A accommodates a rapidly rotating first impeller here shown as a rotary cylindrical brush 42 having relatively soft bristles and being driven at a constant speed to rotate in the direction indicated by arrow 43. The purpose of the bristles of the brush 42 is to remove from the carding 31a successive increments of the layer 41a and to propel the shreds forming such increments to the station B where the shreds accumulate to form a relatively small intermediate supply 44. The propulsion of shreds from the station A to the station B results in a pronounced loosening of fibrous material. The downstream side of the intermediate supply 44 is bounded by a driven carded re fuser drrum 46 which rotates in the direction indicated by the arrow and determines the height of the body or sliver 41b which is being withdrawn from the supply 44 by the carding 31a of the belt 31. It will be noted that the refuser drum 46 rotates counter to the direction of movement of the sliver 41b and that it returns the surplus of shreds into the intermediate supply 44.

The quantity of tobacco shreds in the intermediate supply 44 is monitored by a scanning device here shown as a photoelectric detector unit 47 which transmits appropriate signals to an amplifier 48 whose output is connected with a servomotor 49 (e.g.. an electromagnet) which serves to change the position of the equalizing device 52. When the quantity of tobacco shreds in the intermediate supply 44 reaches a predetermined maximum value, the signal from the detector unit 47 causes the servomotor 49 to reduce the distance between the axis of the equalizing device 52 and the upwardly moving stretch of the belt 31 so that the height of the layer 41a decreases. inversely, when the detector unit 47 detects that the quantity of shreds in the supply 44 has been depleted to a predetermined minimum value, its signal causes the servomotor 49 to move the axis of the equalizing device 52 away from the adjacent stretch of the belt 31 so that the height of the layer 41a increases and the quantity of shreds in the supply 44 begins to increase. The detector unit 47 may comprises a series of discrete photoelectric detectors which are mounted at different levels and each of which comprises a light source and a photosensitive element located in the path of the light beam issuing from the respective light source and designed to produce a signal when the respective light beam is interrupted or is free to reach its photosensitive surface.

The means for converting the sliver 41b into a continuous shower of tobacco shreds comprises a rapidly rotating picker roller 53 located at the downstream end of the upper stretch of the belt 31 (opposite the roller 34) and being driven at a constant speed in a clockwise direction. as viewed in FIG. 2. The shower of tobacco shreds which are expelled from the carding 31a by the picker roller 53 descends onto the upper stretch of an intermediate conveyor 57 which also forms part of the tobacco transporting system and is an endless belt trained over rollers 54, 56. At least one of the rollers 54, 56 is driven to advance the belt 57 in the direction indicated by the arrow. The means for rotating the roller 54 and/or 56 at a constant speed is not shown in the drawing. The upper stretch of the belt 57 advances the accumulating layer or body of tobacco shreds in a direction toward and beyond the right-hand roller 56 whereby the flight spans of lighter tobacco particles 58 are shorter than those of the heavier tobacco particles 58a (mainly tobacco ribs and stem). The heavier particles 580 are thus segregated from the lighter particles 58 and accumulate in a receptacle 61 having in its bottom zone a revolving feed screw 62 which evacuates the heavier particles 58a and delivers them to a conveyor system which in turn feeds the heavier particles to storage or to a device for the making of reconstituted tobacco sheets. A driven roller 59 engages the upper surface of the layer of tobacco shreds on the belt 57 in the region of the roller 56 to insure that each of the shreds forming the layer on the belt 57 is subjected to the same accelerating action whereby the segregation of particles 58 and 58a in the zone downstream of the roller 56 depends mainly or exclusively on the weight and/or shape of propelled particles.

The lighter particles 58 descend onto the upper stretch of an endless apron 63 to form thereon a carpet or body 41c advancing in a direction to the left, as viewed in FIG. 2. The apron 63 is an endless conveyor band which forms part of the aforementioned tobacco transporting system and is trained over rollers 64 and 66. The roller 64 is coaxial with a pulley which is driven by the output shaft 68a of a variable-speed transmission 68 through the intermdiary of an endless toothed belt 67.

Successive increments of the carpet 41c on the upper stretch of the apron 63 move into the range of a rapidly revolving second impeller 69 here shown as a cylindrical brush which is driven at a constant speed by an electric motor 72 through the intermediary of an endless belt 71. The direction of rotation of the impeller brush 69 is indicated by the arrow 73. The peripheral speed of the brush 69 at least equals but preferably exceeds the speed of lengthwise movement of the upper stretch of the apron 63.

The output shaft 68a of the transmission 68 further drives the roller 32 for the carded belt 31 by way of a toothed belt 74. The speed of the output shaft 68a which drives the belts 67, 74 can be regulated by a servomotor 76 to thus determine the rate at which the belt 63 feeds the shreds of the carpet 41c into the range of the impeller brush 69. The input shaft 68b of the transmission 68 receives torque from the main prime mover 27 (FIG. 1) by way of an endless toothed belt 27a.

The lighter tobacco particles 58 (mainly fragments of tobacco leaf laminae) which form the carpet 41c are propelled by the brush 69 at a constant speed to impinge against a baffle or barrier 78 which is located at a level above the channel 1 and causes the deflected particles 58 to form a shower of loose tobacco particles which descend into the channel 1 to deposit on the upper stretch of the belt 2. The barrier or baffle 78 is yeildably mounted in the path of propelled shreds with minimal friction so that it can change its position in dependency on the magnitude of forces transmitted thereto by the propelled material. Such forces are measured by a gauge here shown as a potentiometer 79 whose sliding contact 79a changes its position in response to movements of the baffle 78 whereby the potentiometer 79 furnishes a signal which is proportional to the magnitude of forces acting on the baffle. The potentiometer 79 forms part of a control circuit 81 which further includes a rated value selector 82, e.g., an adjustable potentiometer which can be set to furnish a signal representing the desired quantity of tobacco shreds to be delivered into the channel 1 per unit of time, i.e., the desired weight of tobacco in the plain cigarettes produced by the machine of FIG. 1. The signal from the potentiometer 82 is transmitted to a signal comparing circuit 83 which is connected with a totalizing circuit 87 and transmits signals to a regulator 84 which in turn transmits signals to the transmission ratio adjusting servomotor 76 by way of an amplifier 86. The circuit 87 connects the control circuit 81 with a compensating circuit 88 which includes a tachometer generator 92 connected with the circuit 87 by a signal inverting circuit 89. The generator 92 is driven by the input shaft 68b of the transmission 68 by way of a belt 91 and transmits signals which represent the momentary speed of the print mover 27. The signals furnished by the ta chometer generator 92 and indicating the speed of the prime mover 27 and input shaft 681) of the transmission 68 are inverted by the circuit 89 so that the totalizing circuit 87 receives a signal of lower intensity when the RPM of the prime mover 27 is higher, and vice versa.

The operation of the distributor of FIG. 2 is as follows.

It is assumed that the cigarette rod making machine of FIG. 1 operates at its normal or rated speed which is customarily the higher of two speeds. The main prime mover 27 drives the carded belt 31 by way of the belt 27a, transmission 68, belt 74 and roller 32 so that the belt 31 travels in the direction indicated by arrow 39 and its upwardly sloping stretch between the rollers 32, 33 withdraws from the main supply in the magazine 36 a continuous layer or body 41a of randomly distributed and normally interlaced lighter and heavier tobacco particles 58, 58a. The height of the layer 41a depends on the setting of the equalizing device 52, i.e., on the quantity of tobacco shreds in the intermediate supply 44.

The brush 42 removes from the carding 31a all or nearly all particles of the layer 41a and propels such particles to the station B to continuously replenish the intermediate supply 44 with loose particles 58 and 58a. As mentioned before, the peripheral speed of the brush 42 must exceed the speed of lengthwise movement of the layer 41a on the belt 31. The carding 31a removes loosened tobacco particles from the intermediate sup ply 44 to form the sliver or body 41b which is equalized by the refuser drum 46 and is expelled from the carding 31b by the rapidly rotating picker roller 53. The homogeneousness of the sliver 41b greatly exceeds that of the layer 41a, and this is attributed to the loosening action of the brush 42.

The shower of particles 58, 58a which is formed by the picker roller 53 descends onto the upper stretch of the intermediate conveyor belt 57 and advances toward the driven roller 59. If the quantity of tobacco particles in the intermediate supply 44 rises to or beyond a predetermined value, the signal from the detector unit 47 causes the amplifier 48 to transmit to the servomotor 49 a signal which results in a movement of the equalizing device 52 toward the upwardly moving stretch of the belt 31 so that the height of the layer 410 is reduced. If the intermediate supply 44 is depleted to a predetermined minimum value, the signal from the detector unit 47 effects a movement of the equalizing device 52 away from the belt 3] so that the quantity of tocacco shreads per unit length of the layer 41a increases and the quantity of loosened tobacco particles in the supply 44 increases.

The upper stretch of the belt 57 cooperates with the driven roller 59 to propel the mixture of lighter and heavier tobacco particles 58, 58a into the separating or classifying zone above the right-hand portion of the apron 63. The heavier particles 58a have longer flight spans and enters the receptacle 6] to be evacuated (either periodically or continuously) by the feed screw 62. The lighter particles 58 descend onto a large portion of the upper stretch of the apron 63 and form thereon the carpet or body 41c which is transported toward the brush 69. The latter propels the lighter particles 58a which form the carpet 4T0 at a constant speed against the adjacent side of the barrier or baffle 78 whereby the baffle 78 causes the potentiometer 79 to transmit to the totalizing circuit 87 a signal which is indicative of the force of impact of tobacco particles on the baffle. As shown, the baffle 78 is pivotable about the axis of a shaft 79b which is rigid with the sliding contact 790 of the potentiometer 79. A torsion spring (not shown) which is installed in a housing 790 and acts on the baffle 78 and/or on the shaft 79b opposes the pivotal movement of baffle under the action of tobacco particles 58 which are propelled by the brush 69. The sliding contact 79a is at a standstill when the resistance which is offered by the spring balances the forces which are transmitted by the propelled particles 58. The just discussed spring in the housing 79c may be omitted if the baffle 78 is mounted in such a way that it tends to assume by gravity a neutral position in which it opposes pivotal movements under the action of propelled tobacco particles 58.

The particles 58 which impinge on the baffle 58 descend and form a shower which enters the zone C ofthe channel 1 to form on the belt 2 a narrow stream which is attracted to the belt by the suction chamber 4 to be advanced into the peripheral groove of the suction wheel 6.

The signal which is furnished by the potentiometer 79 is transmitted to the signal comparing circuit 83 by way of the totalizing circuit 87. The circuit 83 further receives a signal from the potentiometer 82 and transmits to the regulator 84 a signal which is amplified at 86 and causes the servomotor 76 to change the speed of the output shaft 680 when the intensity of signal for nished by the circuit 87 differs from the intensity of sig nal furnished by the potentiometer 82. Since the prime mover 27 is assumed to rotate the input shaft 68b at a maximum speed corresponding to the normal operating speed of the cigarette rod making machine, the intensity of signal furnished by the inverting circuit 89 to the totalizing circuit 87 is zero. This is due to the fact that the circuit 89 inverts the signal which is furnished by the tachometer generator 92. Therefore, when the cigarette rod making machine operates at normal speed, the signal which the circuit 87 transmits to the signal comparing circuit 83 is identical with the signal furnished by the potentiometer 79. If the quantity of tobacco particles 58 which are being propelled against the baffle 78 equals the quantity represented by the setting of the potentiometer 82, the output signal from the circuit 83 to the regulator 84 is zero and the speed of the output shaft 68a remains unchanged.

if the quantity of tobacco particles 58 which are pro pelled at a constant speed against the baffle 78 decreases (for example, because the ratio of heavier particles 58a to lighter particles 58 on the belt 57 increases so that a larger proportion of the sliver 41b is being fed into the receptacle 61, or because the quantity of tobacco shreds in the magazine 36 and/or intermediate supply 44 has been depleted and the belt 3| cannot transport a sliver 41b of desired height), the intensity of signal which is furnished by the potentiometer 79 decreases and the circuit 83 transmits to the regulator 84 a signal which is equal to the difference between the signals from the potentiometers 79, 82 whereby the servomotor 76 changes the ratio of the transmission 68, i.e., the belt 31 is driven at a higher speed so that it can withdraw from the magazine 36 larger quantities of tobacco shreds per unit of time. The speed of the tachometer generator 92 remains unchanged because the servomotor 76 does not influence the speed of the input shaft 68b. When the potentiometer 79 detects the increased rate of tobacco propulsion against the baffle 78, the intensity of its signal to the circuit 87 increases and the circuit 83 terminates the transmission of a signal which results in acceleration of the output shaft 680.

If the quantity of tobacco particles 58 which are caused to impinge on the baffle 78 per unit of time exceeds that quantity which is selected by the setting of the potentiometer 82, the potentiometer 79 furnishes a signal which is compared with the signal from the potentiometer 82 and the circuit 83 transmits a signal which causes the servomotor 76 to reduce the speed of the output shaft 680. The belt 31 is then driven at a reduced speed and removes from the magazine 36 less tobacco per unit of time so that the quantity of particles 58 which impinge against the baffle 78 per unit of time (and hence the baffle pivoting action of such particles) decreases accordingly. This is sensed by the potentiometer 79 which causes the circuit 83 to terminate the deceleration of the output shaft 680.

When the cigarette rod making machine of FIG. 1 is being started, the prime mover 27 at first rotates at a starting speed which is less than the aforementioned normal operating speed. The belt 2 is also driven at a lesser speed. Therefore, it is necessary to insure that the signal from the potentiometer 79 (which then indicates that the particles 58 impinging upon the baffle 78 transmit a force which is weaker than the force which is furnished while the cigarette rod making machine operates at normal speed) cannot result in undue acceleration of the belt 31. This is the function of the compensating circuit 88. As mentioned before, the circuit 89 inverts the signal which is furnished by the tachometer generator 92. When the prime mover 27 operates at the relatively starting speed, the signal from the tachometer generator 92 is relatively weak and, therefore, the circuit 89 furnishes to the totalizing circuit 87 a signal which is added to the signal from the potentiometer 79. Consequently, the intensity of signal which is furnished from the circuit 87 to the circuit 83 is sufficient to pre vent an acceleration of the output shaft 680 by way of the regulator 84, amplifier 86 and servomotor 76. In other words, the circuit 88 compensates for the difference between the normal signal from the potentiometer 79 (when the prime mover 27 operates at normal speed) and the weaker signal which is furnished by the potentiometer 79 when the prime mover 27 operates at the relatively low starting speed. It can be said that the circuit 88 insures that the rate of tobacco feed into the channel I is proportional to the speed of the prime mover 27.

Since the impeller brush 69 propels all particles of the body or carpet 41c on the apron 63 at the same speed, the magnitude of the force acting upon the barrier or baffle 78 is invariably proportional to the quantity of tobacco particles per unit length of the carpet 41c. Consequently, the signal which is furnished by the potentiometer 79 can be used for accurate regulation ofthe rate of tobacco withdrawal from the main supply in the magazine 36. All that is necessary is to compare such signal with the signal which is furnished by the potentiometer 82 (and which indicates the desired weight of plain cigarettes) and to adjust the rate of tobacco withdrawal from the magazine 36 as a function of the difference between the intensities of the two signals. The compensating circuit 88 insures that the signal from the potentiometer 79 cannot change the speed of the output shaft 680 in response to changes in the speed of the input shaft 68b, i.e., in response to intentional changes in the speed of the prime mover 27 and the resulting changes in speed of the output shaft 68 a and belt 31.

The feature that the impeller brush 69 acts on a body of tobacco whose height is only a fraction of its width insures that all or practically all particles of tobacco which are propelled by the brush 69 transmit to the baf- He 78 a certain force to thus insure that the extent of pivotal movement of the baffle (and hence the intensity of the signal which is furnished by the potentiometer 79) is an accurate indicator of the quantity of tobacco particles per unit length of the carpet 41c. When the tobacco particles are fed to the brush 69 in the form of a wide carpet of relatively small height. the particles are highly unlikely to transmit energy to each other, i.e., the particles are highly unlikely to deform each other. The motor 72 insures that the speed of the brush 69 is not dependent on the changes in speed of the belt 31, either in response to a signal from the potentiom eter 79 or in response to a change in the speed of the prime mover 27. This insures that the magnitude of force which is transmitted to the baffle 78 is invariably a function of the quantity of tobacco per unit length of the carpet 41c. In other words, the particles which are being propelled against the baffle 78 invariably travel at a predetermined constant speed which is not af fected by the speed at which the particles are being withdrawn from the magazine 36.

The tobacco particles which form the carpet 41a cannot pile up in front of the brush 69 because the latter is driven at a speed which at least equals but preferably exceeds the maximum speed of lengthwise movement of the apron 63.

FIG. 3 illustrates a portion of a modified distributor. All such parts which are clearly analogous to or identical with the corresponding parts of the distributor shown in FIG. 2 are denoted by similar reference characters plus 100. The tobacco shower which is formed by the barrier or baffle 178 is accelerated at a level above the channel 101 by means of a rotary accelerating brush 193 which is driven in a counterclockwise direction, as viewed in FIG. 3, and extends along the full length of the stream forming zone C (see also FIG. 4). The brush 193 is driven at a constant speed by a suitable motor, not shown, and cooperates with a substantially V-shaped stationary wall member 194. The

parts

193, 194 define a funnel 196 which receives lighter tobacco particles from the baffle 178. The tobacco guiding surface of the wall member 194 is preferably corrugated or undulated as considered in the axial direction of the accelerating brush 193 (see FIG. 4).

The operation of the distributor which includes the structure of FIGS. 3 and 4 is as follows.

The brush 169 propels successive increments of the carpet or body l4lc against the adjacent surface of the baffle 178 which causes the associated potentiometer (not shown) to furnish signals which are indicative of the combined force of impact of tobacco particles per unit of time. The tobacco particles of the carpet 141s transmit their entire kinetic energy to the baffle 178. Thereupon, the particles descend by gravity and enter the funnel 196 to be engaged and propelled by the bristles of the rotating accelerating brush 193. The bristles of the accelerating brush 193 actually contact the adjacent surface of the wall member 194 to thus insure that each and every particle of fibrous material accumulating in the hopper 196 is engaged and propelled by the bristles toward and into the channel 101. The corrugated or undulated surface of the wall member 194 insures that the duration 'of engagement of different bristles on the brush I93 with the wall member I94 varies from section to section of the wall member with the result that the particles are propelled into the channel I01 in different directions, i.e., not as a highly condensed curtain but rather as a divergent shower of dis crete particles. Such manner of propelling the particles into the channel 101 is desirable because the narrow stream which grows in the zone C on the upper stretch of the foraminous belt 102 extends along the full width D of the channel L Furthermore, the stream in the channel 101 is highly homogeneous which is a very important factor in the making of fillers for wrapped tobacco rods which are to be subdivided to yield satisfactory plain cigarettes of unit length of multiple unit length.

The accelerating brush 193 cooperates with the wall member 194 to enhance the homogeneousness of the narrow tobacco stream in the channel 101. Thus, the brush 193 imparts to the particles of tobacco kinetic energy downstream of the baffle 178, i.e., downstream of the point where the particles have been relieved of the energy which was imparted thereto by the impeller brush 169. It was found that the uniformity particle distribution in the stream which grows on the upper stretch of the belt 102 is much more satisfactory that in heretofore known distributors and also more satisfactory than in such distributors (see FIG. 2) wherein the particles are allowed to descend into the channel by gravity after impinging against the baffle.

FIG. 5 shows a modification of the structure which is illustrated in FIGS. 3 and 4. All such parts of the structure shown in FIG. 5 which are clearly analogous to or identical with the corresponding parts of the structure of FIGS. 3-4 are denoted by similar reference characters plus 100. The main difference between the structures of FIGS. 34 and FIG. 5 is that the upper portion of the wall member 294 is hingedly connected to the frame of the cigarette rod making machine, as at 297, and that the lower portion of the wall member 294 is articulately connected to a vibrator 298 by means of a link 299. The vibrator 298 includes an electric motor whose output shaft carries a disk having an eccentric pin which is attached to the left-hand end portion of the link 299, as viewed in FIG. 5. The right-hand surface of the wall member 294 need not be of undulate or corrugated shape because the wall member 294 is periodically moved toward and away from the axis of the rapidly rotating accelerating brush 293. Such movements of the wall member 294 insure that the particles of tobacco entering the hopper 296 are spread apart and enter the channel 201 along the full width of the upper stretch of the foraminous belt 202. The particles which reach the belt 202 are attracted thereto by the suction chamber 204 whose top wall 203 is provided with a large number of ports to permit the flow of minute air currents from the interior of the channel 201 above the upper stretch of the belt 202 into the suction chamber.

FIG. 6 illustrates a further gravity type distributor which is similar to the distributor of FIG. 2 and wherein nearly all such parts which are analogous to or identical with the corresponding parts of the distributor of FIG. 2 are denoted by similar reference characters plus 300. The carding 3310 of the endless conveyor belt 331 draws from the magazine 336 a continuous layer or body 341a of a mixture of interlaced lighter and heavier tobacco particles, and the blades of the equalizing device 352 return the surplus or tobacco particles into the main supply in the magazine 336. The latter has a stationary side wall 337 and two end walls (not shown). That stretch of the belt 33] which travels upwardly from the driving roller 332 toward the roller 333 constitutes a moving wall of the magazine 336 and merges into a horizontal stretch which travels in the direction indicated by arrow 339 so as to transport successive increments of the layer 3410 into the range of the first impeller brush 342 which is driven to rotate at a high speed in the direction indicated by arrow 343. The blades of the equalizing device 352 (which is driven to rotate in the direction indicated by arrow 35]) insure that the height of the layer 341a is only a small fraction of its width, i.e., of the width of the belt 331.

The preferably pliable bristles of the cylindrical impeller brush 342 propel the particles of the layer 3410 from the station A to the station B where the particles accumulate to form a relatively small intermediate supply 344. As explained in connection with FIG. 2, the action of the brush 342 upon successive increments of the layer 3410 results in pronounced loosening of tibrous material so that the intermediate supply 344 contains a mass of homogenous particles which can form a highly satisfactory sliver or body 3411). The carded refuser drum 346 equalizes the sliver 341!) and returns the surplus of shredded tobacco into the intermediate supply 344. The drum 346 rotates counter to the direction of lengthwise transport of the sliver 341 b under the action of the carding 331a.

The photoelectric detector unit 347 monitors the quantity of tobacco in the intermediate supply 344 and controls the position of the equalizing device 352 by way of the amplifier 348 and servomotor 349. The latter is preferably a suitable electromagnet whose armature can move the equalizing device 352 nearer to or further away from the adjacent upwardly moving stretch of the belt 331. The signal from the detector unit 347 causes the equalizing device 352 to move nearer to the belt 33] when the quantity of tobacco shreds in the intermediate supply 344 rises and vice versa.

The leading edge of the sliver 34lb advances into the range of rapidly revolving teeth of a picker roller 353 which is adjacent to the roller 334 and showers the loosened particles of tobacco onto the upper stretch of the belt 357 which is trained over the rollers 354, 356 and collects a layer or body 341(- which is propelled into a segregating or classifying zone 358 with assistance from the driven roller 359. The picker roller 353 is driven at a constant speed by a suitable electric motor, not shown. The roller 359 is adjacent to the roller 356 and insures that the accelerating action upon all particles of the layer 341a is the same. The heavier particles 341a" (mainly portions of ribs and/or stem) are propelled into a receptacle 361 containing a feed screw 362 which evacuates the accumulated heavier particles at regular intervals or when necessary. The lighter particles 341d (mainly fragments of tobacco leaf laminae) have shorter flight spans and descend onto the upper stretch of a second impeller here shown as an apron 403 to form thereon a carpet or body which advances in a direction to the left, as viewed in FIG. 6. The apron 403 is an endless belt which is trained over rollers 40], 402 and is driven at a constant speed. The speed of the apron 403 is sufficient to insure that the lighter particles 341d leaving the left-hand end of its upper stretch are propelled against a barrier or baffle 378 which controls the position of the sliding contact of a potentiometer 379 substantially in the same way as described for the potentiometer 79 of FIG. 2. The gap across which the particles 341d are propelled by the apron 403 against the baffle 378 is shown at F. The particles 341d transmit their kinetic energy to the baffle 378 and thereupon descend by gravity onto a further endless belt or apron 363 corresponding to the apron 63 of FIG. 2 and being trained over

rollers

364, 366. The carpet or body 341e of tobacco particles 341d on the upwardly moving upper stretch of the apron 363 is fed into the range of bristles on an accelerating brush 369 which is an elongated cylinder and is rotated in the di rection indicated by arrow 373. The bristles of the brush 369 propel the particles 341d of the carpet 341e into the channel 301 so that such particles form a narrow growing stream on the upper stretch of the conveyor belt 302 above the perforated top wall 303 of the suction chamber 304.

The roller 332 for the carded belt 331 is driven by the output shaft 368a of the variable-speed transmission 368 by way of a toothed belt 374 so that it rotates in the direction indicated by arrow 338. The input shaft 368b of the transmission 368 is driven by the prime mover 327 of the cigarette rod making machine, not shown in FIG. 6. The ratio of the transmission 368 (namely, the speed of the output shaft 368a while the speed of the input shaft 368b remains unchanged) can be varied by an adjustable servomotor 376. As mentioned before, the roller or rollers which drive the belt 357, the roller or rollers which drive the apron 403, the brushes 342 and 369, the roller 359 and the picker roller 353 are rotated at a constant speed, preferably by one or more electric motors, not shown. Thus, the speed of these rotary parts remains unchanged even if the speed of the prime mover 327 is changed from the normal operating speed to a relatively low starting speed or vice versa. The roller 364 and/or 366 for the apron 363 is driven by the main prime mover 327 so that its speed changes in re sponse to changes in operating speed of the cigarette rod making machine and conveyor belt 331.

The barrier or baffle 378 is mounted in such a way that it can change its position under or counter to the force which is applied by the propelled tobacco particles 341d with minimal friction. The potentiometer 379 produces signals which are indicative of the force acting on the baffle 378 and transmits such signals to a totalizing circuit 387 forming part of a compensating circuit 388. The potentiometer 379 forms part of a control circuit 381 which further includes a rated value selecting potentiometer 382. The latter can be adjusted to furnish a signal representing the desired rate of feed of tobacco particles 341d into the channel 301, i.e., the desired weight of plain cigarettes which are being produced by the machine including the distributor of FIG. 6. The setting of the potentiometer 382 actually determines the combined weight of particles 341d which are admitted into the channel 301 per unit of time. Still further, the control circuit 381 includes a signal comparing circuit 383 which is connected with the output of the potentiometer 382 and with a regulator 384 for an amplifier 386 which controls a servomotor 406 provided to determine the angular position of the output element of a transmission 407. The totalizing circuit 387 connects the control circuit 381 with the compensating circuit 388. The latter further includes a tachometer generator 392 which is driven by the input shaft 368b of the transmission 368 through the intermediary of a toothed belt 391 and furnishes signals representing the speed of the prime mover 327. The circuit 387 is connected with the output of the tachometer generator 392 by way of a signal inverting circuit 389. As explained in connection with the circuit 89, the circuit 389 inverts the signal which is furnished by the tachometer generator 392 so that the corresponding input of the circuit 387 receives a signal whose intensity decreases in response to increasing speed of the prime mover 327 and vice versa. This insures that the signal which is furnished by the potentiometer 379 when the rate of tobacco delivery into the channel 301 decreases due to a reduction in the speed of the prime mover 327 (reduction in the output of the cigarette rod making machine) cannot cause an increase in the rate of tobacco feed because this would cause an increase in the weight of plain cigarettes.

The signal from the potentiometer 379 can influence the rate of delivery of tobacco into the channel 301 by way of a hollow intercepting or retaining device 408 which is movable lengthwise of the gap F (i.e., transversely of the apron 403) in directions indicated in FIG. 7 by a double-headed arrow 409. To this end, the intercepting or retaining device 408 is coupled to the bifurcated arm 412 a shifter fork 413 which is connected to the turnable output element 414 of the transmission 407 and constitutes a two-armed lever the lower arm 416 of which constitutes a trip and is movable between two

limit switches

417, 418. Depending on its position, the intercepting device 408 directs a larger or smaller percentage of tobacco particles 341d which are being propelled across the gap F into a pneumatic conveyor pipe 411 which is connected with a suction generating device and serves to transport the intercepted particles 341d back into the magazine 366 so that such particles are returned into the main supply in the magazine. The discharge end of the pipe 411 is shown in FIG. 6 above the upper surface of the supply of tobacco shreds in the magazine 336.

The limit switches 417, 418 are respectively connected to the inputs a of two logic circuits 419, 421 (FIG. 7) of the type known as ANDgates. These switches transmit signals when the intercepting device 408 respectively assumes or approaches its right-hand and left-hand end positions, as shown in FIG. 7, i.e., when the device 408 respectively intercepts a minimum and a maximum quantity of particles 341d. The inputs b of the AND-

gates

419, 421 are connected with the output of an electrical pulse generator 422 which con stitutes a rotary timer clock and transmits pulses to the inputs b by way of a conductor 423. The outputs c of the AND-

gates

419, 421 are respectively connected with

amplifiers

424, 426 which can change the direction of rotation of the servomotor 376 to thereby increase or reduce the speed of the output shaft 3680 of the transmission 368 with attendant changes in the speed of the carded belt 331 while the speed of the prime mover 327 remains unchanged. The polarity of signals furnished by the outputs c of the AND-

gates

419, 421 is selected in such a way that, when the input a of the gate 419 receives a signal from the limit switch 417 (minimal interception of tobacco particles 341d by the device 408), the amplifier 424 transmits to the servomotor 376 a signal which causes the transmission 368 to increase the speed of the output shaft 3680. When the input a of the AND-gate 421 receives a signal from the limit switch 418, the amplifier 426 transmits to the servomotor 376 a signal which results in a deceleration of the output shaft 368a so that the rate of withdrawal of tobacco shreads from the magazine 336 is reduced. The just described regulating circuit serves the purpose of preventing the intercepting device 408 from leaving a predetermined range of its intermediate positions, i.e.. of insuring that the rate of tobacco withdrawal from the magazine 336 corresponds substantially or roughly to the desired rate of tobacco feed into the channel 301. Such regulation of the rate of tobacco withdrawal from the magazine 336 can be termed a coarse or approximate adjustment.

The operation of the distributor of FIGS. 6-7 is as follows.

The prime mover 327 is assumed to drive the ciga rette rod making machine and the belt 331 at a relatively high or normal speed. The carding 331a removes tobacco particles from the magazine 336 to form the layer or body 341a which is equalizied by the blades of the device 352 and advances into the range of bristles on the impeller brush 342. The particles in successive increments of the layer 341a are separated from the carding 3310 by the brush 342 and are propelled from the station A to the station B to form the intermediate supply 344. The belt 331 withdraws from the supply 344 a continuous sliver or body 341!) which is equalized by the refuser drum 346 and is showered by the picker roller 353. The homogeneousness of the sliver 341b greatly exceeds that of the layer 341a, and this is attributed to the loosening action of the brush 342.

The quantity of tobacco particles per unit length of the sliver 34lb is more uniform if the quantity of parti' cles in the intermediate supply does not appreciably deviate from a predetermined average quantity. This is insured by the detector unit 347 which monitors the quantity of tobacco particles in the supply 344 and controls the position of the equalizing device 352 with a view to move the device 352 nearer to the belt 331 when the quantity of tobacco particles in the supply 344 increases, and vice versa.

The particles which are showered by the picker roller 353 accumulate on the upper stretch of the belt 357 and advance toward the driven roller 359.

The belt 357 is driven at a relatively high speed and cooperates with the rapidly rotating roller 359 to propel the particles of the layer 341c into the classifying zone 358 with the resulting separation of lighter and

heavier particles

341d, 341d. The particles 341d have longer flight spans and enter the receptacle 361 whereas the lighter particles 341d descend onto the apron 403 to form thereon a carpet or body which advances toward and across the gap F to impinge against the baffle 378. The height of the carpet of particles 341d on the upper stretch of the arpon 403 is only a small fraction of its width. The apron 403 is an impeller which is driven at a high speed so that it can propel the particles 341d against the baffle 378 whereby the force of such impact determines the intensity of signal which is furnished by the potentiometer 379. The particles 341d rebound on the baffle 378 to thereupon descend by gravity and to form on the arpon 363 a second carpet or body 341a which moves toward the accelerating brush 369. This brush propels the particles 341d of the carpet 341e into the channel 301 whereby the particles form a divergent shower which is converter into a narrow tobacco stream travelling with the belt 302 toward the peripheral groove of the suction wheel in the cigarette rod making machine (see the wheel 6 of FIG. 1). The apron 363 performs the function of the

wall member

194 or 294.

The signal from the potentiometer 379 is transmitted to the totalizing circuit 387 which adds such signal to the signal which is furnished by the inverting circuit 389. The resulting signal is transmitted to the circuit 383 which compares it with the signal from the potentiometer 382. The intensity of signal from the inverting circuit 389 is preferably zero when the prime mover 327 is driven at the normal speed. When the prime mover 327 operates at less than normal speed, the signal from the inverting circuit 389 is added to the relatively weak signal from the potentiometer 379 to pre vent an increase in the weight of plain cigarettes.

When the signal which is being transmitted from the totalizing circuit 387 to the signal comparing circuit 383 deviates from the signal which is generated by the potentiometer 382, the regulator 384 causes the amplifier 386 to actuate the servomotor 406 which causes the transmission 407 to change the angular position of the shifter fork 413. The latter changes the position of the intercepting device 408 so that the device 408 intercepts or retains a larger or smaller quantity of particles 341d which travel across the gap F toward the baffle 378. The intercepted particles 341d enter the pipe 411 and are returned into the magazine 336. The effect of adjustment of the intercepting device 408 is felt practically immediately, i.e., with a delay which merely corresponds to the time required for a particle 341d to travel across the gap F. The just described adjustment enhances the homogeneousness of the tobacco shower which enters the channel 301.

When the cigarette rod making machine is in operation for an extended period of time, the rate of tobacco withdrawal from the magazine 336 is likely to deviate considerably from the desired rate. The deviation may be an upward or a downward deviation. In such instances, the intercepting device 408 might not be capable of compensating for substantial deviations because it has already assumed the one or the other of its end positions. This necessitates a coarse or approximate adjustment of the rate of tobacco withdrawal to roughly correspond to the desired rate of tobacco feed into the channel 301. Such coarse adjustment is effected by the

limit switch

417 or 418 each of which is preferably mounted in such a way that it is actuated by the trip 416 shortly before the intercepting device 408 reaches the respective end position. The switch which is actuated by the trip 416 furnishes a signal to the input a of the corresponding AND-gate 419 or 421. The arrangement is such that, when the input a of the AND-gate 419 or 421 receives a signal, it allows the transmission of pulses from the pulse generator 422 to the

corresponding amplifier

424 or 426 to thus effect an appropriate adjustment of the servo-motor 376 for the transmission 368. The number of pulses which are permitted to pass from the pulse generator 422 by way of the AND-gate 419 or 421 determines the extent of adjustment of the transmission 368 and thus the extent to which the speed of the belt 331 is increased or reduced. The belt 331 then draws from the magazine 336 larger or smaller quantities of tobacco particles per unit of time in order to insure that the average rate of tobacco withdrawal at least approximates the desired rate of tobacco feed into the channel 301.

The width of the intercepting device 408 need not equal the width of the apron 403 (see FIG. 7). Thus, the device 408 need not be capable of intercepting all of the particles 341d which travel across the gap F.

An advantage of the intercepting device 408 is that it can compensate for slight fluctuations in the rate of tobacco transport toward the baffle 378 without necessitating a change in the speed of the belt 331, i.e., a change in the rate of tobacco withdrawal from the mag azine 336. This intercepting device operates in the path (gap F) wherein the particles 341d travel at a predetermined constant speed which is determined by the apron 403. The latter performs the function of the

impeller

69, 169 or 269. Though it would be possible to guide the intercepting device into the body if propelled tobacco particles 341d from above or from below, the mounting of the device 408 which is shown in FIGS. 6 and 7 is preferred at this time because, as the device 408 moves transversely of the impeller apron 403 and lengthwise of the gap F, it is capable of intercepting accurately determined quantities of particles since the height of the body of propelled particles is relatively small and the width of such body greatly exceeds its height. Furthermore, and as mentioned above, such mounting of the intercepting device 408 insures that the rate of tobacco feed against the baffle 378 can be changed with a negligible delay which equals the interval required by a particle travel across the gap F.

The accelerating brush 369 cooperates with the apron 363 to accelerate all particles 341d downstream of the baffle 378 and to propel the particles into the channel 301 along the full width of the upper stretch of the belt 302. Such acceleration and distribution of particles insures the formation of a highly satisfactory homogeneous tobacco stream which is ready to be converted into a filler rod.

Referring finally to FIG. 8, there is shown a portion of a distributor which constitutes a modification of the distributor of FIGS. 6 and 7. The distributor of FIG. 8 comprises a modified arrangement for insuring that the rate of tobacco withdrawal from the magazine (not shown) at least approximates the desired rate of tobacco feed into the channel (not shown). The signal from the

amplifier

424 or 426 of FIG. 7 (not shown in FIG. 8) is transmitted to a servomotor 576 which can adjust the ratio of a variable-speed transmission 568 for an interval of time which corresponds to the duration of signal from the

amplifier

424 or 426. When the trip 416 of FIG. 7 actuates the limit switch 417, the servomotor 576 is caused to reduce the speed of the output shaft 5680 of the transmission 576 whereby the speed of the corded belt 531 is reduced and the rate of tobacco withdrawal from the magazine decreases. When the trip 416 actuates the limit switch 418 of FIG. 7, the servomotor 576 increases the speed of the output shaft 568a so that the rate of tobacco withdrawal from the magazine increases.

The just described distributor is also capable of insuring that the rate of tobacco withdrawal from the main source of supply in the magazine approximates the desired rate of tobacco feed into the channel. The refuser drum 546 of FIG. 8 is driven by the input shaft 568b of the transmission 568 and its rotational speed influences the quantity of tobacco per unit length of the sliver 541b, because at a higher rotational speed of the refuser drum 546 more tobacco will be removed out of the cardings 531a of the belt 531 and vice versa. All other parts shown and referenced in FIG. 8 but not specifically mentioned are identical with or clearly analogous to the similarly referenced parts shown in FIG. 6.

An important advantage of the improved method and apparatus is that each unit length of the body of fibrous material which reaches the channel in a distributor for use in cigarette rod making or analogous machine invariably contains the same quantity of particles and that such uniformity in the rate of particle feed into the channel can be achieved in a fully automatic way, i.e.. without requiring any attention on the part of attendants. The compensating

circuit

88 or 388 insures that those changes in the magnitude of force transmitted to the baffle which develop when the prime mover of the machine is caused to operate at a different speed cannot result in substantial changes in the rate of particle withdrawal from the main source, i.e., that the weight of final products (such as cigarettes) remains the same, irrespective of whether the machine is being operated at normal speed or other than normal speed.

The apparatus of FIGS. 6 to 8 exhibits the additional advantage that the regulation in the rate of particle transport into the channel 301 can be effected practically without any delay and also that the apparatus is capable of bringing about an automatic approximation of the rate of particle withdrawal from the main source to the desired rate of particle feed into the tobacco channel. Thus, the intercepting device 408 is merely required to perform fine adjustments because the coarser adjustments are effected in response to signals from the

limit switches

417 and 418.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adpapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of our contribution to the art and. therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. A method of determining the rate of feed of a moving body consisting of fibrous particles at least some of which have different sizes, shapes and/or weights particularly of determining the rate of feed of tobacco shreds or filter material in the distributor of a cigarette rod making or filter rod making machine, comprising the steps of accumulating and maintaining a supply of fibrous particles; withdrawing from said supply a continuous body of fibrous particles at a randomly varying rate and transporting the particles of said body along a predetermined path; imparting to the particles of successive increments of said body a predetermined constant speed, at least in a portion of said path; establishing a barrier across said portion of said path so that the particles which move at said constant speed are propelled in unsupported condition and impinge against the barrier with a force which is proportional to the quantity of particles per unit length of the body; measuring said force and producing a signal which is indicative of the quantity of fibrous particles per unit length of said body; and utilizing said signal to remove by in- 21 tercepting varying quantities of propelled unsupported fibrous particles so that the quantity of removed particles increases or decreases when the quantity of particles per unit length of said body exceeds or is below a predetermined quantity, respectively.

2. A method as defined in claim 1, further comprising the step of changing the rate of withdrawal of fibrous particles from said supply independently of said signal and automatically compensating for the resulting change in the intensity of said signal.

3. A method defined in claim 1, further comprising the step of imparting to said body of fibrous particles in said portion of said path the shape of a layer whose height is a small fraction of its width.

4. A method as defined in claim 1, further comprising the step of accelerating the fibrous particles in a second portion of said path located downstream of said first mentioned portion, and converting the thus accelerated particles into a continuous narrow stream having a width not substantially exceeding its height.

5. A method as defined in claim 4, wherein said accelerating step comprises subjecting the fibrous particles to a mechanical accelerating action.

6. A method as defined in claim 4, wherein said accelerating step includes converting the fibrous particles into a divergent shower.

7. Apparatus for determining the rate of feed of a moving body consisting of fibrous particles at least some of which have different sizes, shapes and/or weights, particularly for determining the rate of feed of tobacco shreds or filter material in the distributor of a cigarette rod making or filter rod making machine, comprising a magazine arranged to accommodate a supply of fibrous particles; transporting means arranged to draw from said supply a continuous body of fibrous particles at a randomly varying rate and to transport said body lengthwise along a predetermined path; channel means remote from said magazine and including means for receiving and conveying at least a portion of said body; a barrier extending across a predetermined portion of said path; impeller means for propelling the particles of successive increments of said body against said barrier at an at least substantially constant speed whereby said barrier is subjected to the action of a force whose magnitude is proportional to the quantity of particles per unit length of said body; and means for measuring the magnitude of said force, said measuring means including means for generating signals indicating the magnitude of said force and further comprising intercepting means located between said impeller means and said barrier and movable relative to said path to intercept different portions of said body of fibrous particles, and control means for moving said intercepting means in response to said signals.

8. Apparatus as defined in claim 7, wherein said bar rier is positioned to change the direction of movement of fibrous particles in said path.

9. Apparatus as defined in claim 7, wherein said im peller means is arranged to propel the particles against said barrier at a constant speed which at least equals the speed of said transporting means.

10. Apparatus as defined in claim 9, wherein said impeller means includes at least one rotary brush.

11. Apparatus as defined in claim 7, wherein said transporting means includes an endless apron arranged to feed successive increments of said body into the range of said impeller means.

12. Apparatus as defined in claim 7, wherein said transporting means includes a conveyor arranged to withdraw said body of fibrous particles from said magazine and variable-speed drive means for said conveyor, said measuring means including means for generating signals indicating the magnitude of said force and fur ther comprising control means for changing the speed of said drive means in response to said signals.

13. Apparatus as defined in claim 7, wherein said impeller means is arranged to propel the particles in the form of a carpet having a height which is a smail fraction of the width thereof, said intercepting means being movable transversely of said carpet to intercept a varying portion thereof while permitting the remaining portion of the carpet to impinge against said barrier.

14. Apparatus as defined in claim 7, wherein said measuring means comprises means for generating first signals indicating the magnitude of said force and further comprising primer mover means arranged to drive at least a portion of said transporting means at a plurality of speeds, means for generating second signals indicative of the speed of said prime mover means, control means for changing the rate of delivery of particles to said channel means in response to said first signals, and compensating means responsive to said second signals and arranged to prevent changes in the rate of de livery of particles in response to those first signals which are generated as a result of changes in the speed of said prime mover means.

15. Apparatus as defined in claim 7, further comprising means for accelerating the particles between said barrier and said channel means.

16. Apparatus as defined in claim 15, wherein said accelerating means comprises at least one rotary brush.

[7. Apparatus as defined in claim 16, wherein said accelerating means further comprises a wall member defining with said brush a funnel for reception of fibrous particles from said barrier.

18. Apparatus as defined in claim 17, wherein said wall means has an undulate surface contacted by said brush.

19. Apparatus as defined in claim 17, further comprising means for imparting to said wall means recurrent movements relative to said brush.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION July 23,1974

Patent No. 3 825 Dated Inventor( Harry DAVID and RUDSZINAT It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the cover sheet Harry DAVIS should read -Harry DAVID-- Signed and sealed this 19th day of November 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. Attesting Officer C. MARSHALL DANN Commissioner of Patents -'ORM Po-wso (Hi-69) USCOMM-DC 00376-P69 U 5 GOVIIIIIIENT 'IINVIIIG OFFICI: 930

Claims

1. A method of determining the rate of feed of a moving body consisting of fibrous particles at least some of which have different sizes, shapes and/or weights particularly of determining the rate of feed of tobacco shreds or filter material in the Distributor of a cigarette rod making or filter rod making machine, comprising the steps of accumulating and maintaining a supply of fibrous particles; withdrawing from said supply a continuous body of fibrous particles at a randomly varying rate and transporting the particles of said body along a predetermined path; imparting to the particles of successive increments of said body a predetermined constant speed, at least in a portion of said path; establishing a barrier across said portion of said path so that the particles which move at said constant speed are propelled in unsupported condition and impinge against the barrier with a force which is proportional to the quantity of particles per unit length of the body; measuring said force and producing a signal which is indicative of the quantity of fibrous particles per unit length of said body; and utilizing said signal to remove by intercepting varying quantities of propelled unsupported fibrous particles so that the quantity of removed particles increases or decreases when the quantity of particles per unit length of said body exceeds or is below a predetermined quantity, respectively.

3. A method as defined in claim 1, further comprising the step of imparting to said body of fibrous particles in said portion of said path the shape of a layer whose height is a small fraction of its width.

8. Apparatus as defined in claim 7, wherein said barrier is positioned to change the direction of movement of fibrous particles in said path.

9. Apparatus as defined in claim 7, wherein said impeller means is arranged to propel the particles against said barrier at a constant speed wHich at least equals the speed of said transporting means.

12. Apparatus as defined in claim 7, wherein said transporting means includes a conveyor arranged to withdraw said body of fibrous particles from said magazine and variable-speed drive means for said conveyor, said measuring means including means for generating signals indicating the magnitude of said force and further comprising control means for changing the speed of said drive means in response to said signals.

13. Apparatus as defined in claim 7, wherein said impeller means is arranged to propel the particles in the form of a carpet having a height which is a small fraction of the width thereof, said intercepting means being movable transversely of said carpet to intercept a varying portion thereof while permitting the remaining portion of the carpet to impinge against said barrier.

14. Apparatus as defined in claim 7, wherein said measuring means comprises means for generating first signals indicating the magnitude of said force and further comprising primer mover means arranged to drive at least a portion of said transporting means at a plurality of speeds, means for generating second signals indicative of the speed of said prime mover means, control means for changing the rate of delivery of particles to said channel means in response to said first signals, and compensating means responsive to said second signals and arranged to prevent changes in the rate of delivery of particles in response to those first signals which are generated as a result of changes in the speed of said prime mover means.

17. Apparatus as defined in claim 16, wherein said accelerating means further comprises a wall member defining with said brush a funnel for reception of fibrous particles from said barrier.