US3903901A

US3903901A - Method and apparatus for manipulating tobacco

Info

Publication number: US3903901A
Application number: US846697A
Authority: US
Inventors: Waldemar Wochnowski
Original assignee: Hauni Werke Koerber and Co KG
Current assignee: Koerber AG
Priority date: 1968-08-23
Filing date: 1969-08-01
Publication date: 1975-09-09
Anticipated expiration: 1992-09-09
Also published as: GB1285771A; NL6909756A; NL7811238A

Abstract

A continuous stream of tobacco leaves, tobacco leaf laminae, ribs or shreds is formed by accumulating a determinate supply of tobacco, continuously evacuating tobacco from the supply in the form of a stream, weighing successive increments of the stream, and changing the rate of evacuation when the weight of an increment or of a series of increments deviates from a desired value. The supply of tobacco is accumulated by intermittently or continuously removing tobacco from bales of compacted tobacco leaves or by removing tobacco leaves, shreds, ribs or laminae from a hopper which contains a large accumulation of particulate material. The determinate supply is not necessary if the removal of tobacco from the bales takes place continuously but at a variable rate.

Description

United States Patent 1 1 Wochnowski Sept. 9, 1975 1 1 METHOD AND APPARATUS FOR MANIPULATING TOBACCO 5] Inventor: Waldemar Wochnowski,

HamburgVolksdorf, Germany [22] Filed: Aug. 1, 1969 [21] Appl. No: 846,697

[30] Foreign Application Priority Data Mar. 21, 1969 Germany 1714466 Apr. 21, 1969 Germany 1782380 [52] U.S.Cl 131/21 R; 131/22 R; 131/149 [51] Int. Cl .1 A241) 07/14 [58] Field ofSearch .1 131/21,21A,21 13,22, 131/27 A,108,109,149, 21 R [56] References Cited UNITED STATES PATENTS 2,090,252 8/1937 Damm 131/22 A X 2,103,400 12/1937 Weckerly 131/22 A UX 2,163,415 6/1939 Stephano 131/21 B 2,262,862 11/1941 Rundell 11111 1. 131/149 X 2,796,066 6/1957 Crcuzburg 1. 131/108 2,799,278 7/1957 Bogarty 1 131/149 X 2,8151759 12/1957 Molins ct alt 131/21 B 21827058 3/1958 Bogarty .1 131/108 2,954,775 10/1960 Radley ct a1. 1. 131/21 B FOREIGN PATENTS OR APPLICATlONS 2401574 11/1911 Germany 1. 131/109 1.120.961 12/1961 Germany v 1 v 1 1 1 131/149 331,333 7/1930 United Kingdom 111111 131/22 A 3851946 2/1933 United Kingc1om..11v 1. 131/21 A 506,883 6/1933 United Kingdom... 131/21 8 600,237 4/1948 United Kingdom .l 131/21 A Primary Exuminer.loseph S, Reich Attorney, Agem, or Firm-Michael S. Striker [5 7] ABSTRACT A continuous stream of tobacco leaves, tobacco leaf laminae, ribs or shreds is formed by accumulating a determinate supply of tobacco, continuously evacuating tobacco from the supply in the form of a stream, weighing successive increments of the stream. and changing the rate of evacuation when the weight of an increment or of a series of increments deviates from a desired value. The supply of tobacco is accumulated by intermittently or continuously removing tobacco from bales of compacted tobacco leaves or by removing tobacco leaves, shreds, ribs or laminae from a hopper which contains a large accumulation of partic ulate material. The determinate supply is not neces sary if the removal of tobacco from the bales takes place continuously but at a variable rate.

9 Claims, 6 Drawing Figures PATENTEDSEP 191s 3.903.901

SHEET 3 [1F 11 INVE N TOR W M W ATTORNEY METHOD AND APPARATUS FOR MANIPULATING TOBACCO BACKGROUND OF THE INVENTION The present invention relates to a method and apparatus for manipulating whole or comminuted tobacco leaves. More particularly. the invention relates to a method and apparatus for converting a supply of condensed or loose tabacco into a substantially uniform carpet or stream of tobacco leaves. tobacco leaf laminae, ribs and/or shreds.

Virginia and Burley tobaccos are frequently stored in condensed or compacted condition in the form of untied bales. known as containing so-called loose leaf tobacco. In a tobacco processing plant, the bales must be broken up and their contents converted into a stream or mat which is transported to a series of processing stations. such as drying, moistening, heating, commi nuting stations and/or others. At the present time, the bales are normally broken by hand, mainly because it is difficult to convert a bale of condensed tobacco leaves (particularly leaves of Virginia or Burley tobacco) into a uniform carpet which is ready for transport to various processing stations.

Similar problems arise in connection with withdrawal of tobacco leaf laminae, tobacco ribs and tobacco shreds from a hopper or a like source. Such problems are encountered. for example. when fragments of tobacco leaves are withdrawn from a large supply for transport to a blending station or to a rod cigarette machine.

SUMMARY OF THE INVENTION An object of my invention is to provide a method for converting a supply of whole or comminuted tobacco leaves into a carpet, a mat or stream of tobacco wherein each increment contains the same or nearly the same quantity of tobacco.

Another object of the invention is to provide a method of converting compacted tobacco into a carpet or stream wherein each unit length contains the same or nearly the same quantity of leaves or fragments.

A further object of the invention is to provide a novel method of converting a supply of loose or substantially loose tobacco leaves or fragments of tobacco leaves into a carpet or stream wherein the weight of each unit length remains within a predetermined range.

An additional object of the invention is to provide a novel and improved apparatus for converting a supply of condensed or loose tobacco leaves into a continuous carpet or stream of tobacco.

Still another object of the invention is to provide the apparatus with novel conveying means and with novel means for controlling and regulating the operation of such conveying means.

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 opera tion. together with additional features and advantages thereof, will be best understood upon perusal of the following detailcd description of certain specific embodiments with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic elevational view of an apparatus which comprises a single monitoring device and is utilized to convert bales of condensed tobacco leaves into a continuous stream of leaves;

FIG. 2 is a fragmentary elevational view ofa second apparatus which comprises two monitoring devices;

FIG. 3 is a fragmentary side elevational view of a third apparatus which does not employ a magazine for tobacco leaves;

FIG. 4 is a fragmentary side elevational view of a fourth apparatus which constitutes a modification of the apparatus shown in FIG. 2;

FIG. 5 is a schematic partly elevational and partly sectional view of a fifth apparatus which is utilized to convert a supply of loose tobacco into a continuous stream; and

FIG. 6 is a fragmentary partly elevational and partly sectional view of a sixth apparatus which constitutes a distributor for tobacco shreds.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. I, there is shown an apparatus which is employed for converting the contents of accumulations or bales 2 of condensed Virginia or Burley tobacco into a continuous or discontinuous stream of tobacco leaves. The apparatus comprises at removing or bale breaking conveyor I which serves to break up successively delivered bales 2 into a carpet or stream of advancing tobacco leaves. The removing conveyor l comprises an endless carded belt 3 which is trained over rollers 4, 5 and has tobacco cntraining spikes 7 arranged to transport tobacco leaves along nearly vertical path from a lower level to a higher level and to dump the leaves into a magazine 17. The operation ofthe belt 3 is not unlike that of an elevator. The removing conveyor 1 further comprises a second endless belt 8 which is trained over rollers 81!, 8/) and has an upper stretch which supports the bales 2 and urges the front face of the foremost bale into the range of ascending spikes 7 on the left-hand stretch ofthc belt 3. The drive means for the endless belts 3 and 8 comprises a transmission 9 whose input shaft 13 is driven by an electric de motor I4 and which comprises two output shafts I I. 12 serving to respectively drive the roller 6 of the belt 3 and the roller 81) of the belt 8. The speed of the belt 8 is less than the speed of the belt 3. The drive including the parts 9 to 14 operates intermittently, the motor 14 is started only when the alternate supply 18 of tobacco leaves 15 in the magazine [7 is depleted to a predetermined value. The control unit which starts and stops the motor 14 of the drive for the belts 3, 8 is shown at 16. The magazine 17 is designed to accomodate a relative small but determinate supply or store 18 of loose tobacco leaves I5, Le, a supply which is either constant or wherein the .quantity of leaves fluctuates within a known and preferably narrow range. and the control unit I6 comprises a monitoring device includ ing a photoelectric detector having a light source (not shown) and a photosensitive receiver I9 which produces an electric signal when the supply 18 of tobacco leaves 15 in the magazine 17 is depleted and reaches a level at which the light source is free to send light rays against the photosensitive surface of the receiver 19. The control unit 16 further comprises a conventional adjustable time delay device 21 which is electrically connected with the receiver 19, an amplifier 22 is series with delay device 21, and an electric switch including a relay 23 in circuit with the motor 14.

The apparatus further comprises an evacuating conveyor 24 having an endless carded belt 29 which is trained over

rollers

27, 28 and is provided with spikes 26. The left-hand stretch of the belt 29 travels upwardly along the adjacent open side of the magazine 17 so that its spikes 26 can transport tobacco leaves upwardly and over the roller 28 whereby such leaves form a continuous stream which is supplied to the upper stretch of an endless receiving conveyor 31. The latter transports the leaves to a further destination for exam plc, into a destalking or shredding machine. not shown The lower roller 27 of the belt 29 is driven by an electric d-c motor through the intermediary of a belt or chain 25a.

Still further the apparatus of FIG. 1 comprises a feeding unit 32 which serves to supply bales 2 onto the upper stretch of the belt 8. This feeding unit 32 is designed to dump bales onto the lefthand portion of the belt 8 and includes a skeleton frame dimensioned to receive a carriage or dolly 35 containing a barrel which accommodates a bale 2. Feeding units of the type shown in FIG. l are produced by Hauni-Werke. Korbcr & Co, K. (1, of Hamburg-Bergeclorf, Western Germany and are known as Kippvorrichtung WK." The means for tilting the frame 30 from the solid-line position to the phantom-like position 30' and vice versa comprises a reversible electric gear motor 34 which is started in response to closing of a master switch 33. The output shaft 36 of the transmission 34a which is driven by the motor 34 carries a sprocket wheel for an endless chain 37 which is trained over a second sprocket wheel 38 affixed to a horizontal shaft 29 of the frame 30. The dolly 35 is optional because the feeding unit 32 may comprise a conveyor which delivers bales 2 directly into the frame 30.

THE OPERATION A dolly 35 (with an open-top barrel 40 therein] is introduced into the skeleton frame 30 while the latter dwells in the solid-line position. The dolly 35 can transport barrels 40 from a large magaiine (not shown) along rails which terminate at the feeding unit 32. When the station above the left-hand portion of the upper stretch of the belt 8 is unoccupied an operator closes the master switch 33 to start the motor 34 whereby the output shaft 36 rotates in a clockwise direction and causes the shaft 39 to pivot the frame 30 and the dolly 35 therein to the positions 30', 35 shown by phantom lines. The bale then leaves the barrel 40 by gravity and descends onto the belt 8. The direction of rotation of the motor 34 is thereupon reversed so that the frame 30 returns to the so|idline position and that the operators can replace the dolly 35 with a dolly which accommodates a full barrel 40. If desired. the apparatus may be provided with a scanning device (c.g. a photosensitive detector) which scans the upper stretch of the belt 8 and automatically closes the master switch 33 when the belt 8 is ready to receive a fresh bale 2. Also. the operation of the feeding unit 32 can be programmed in such a way that a dolly 35 with an empty barrel 40 thereon is automatically evacuated from the frame 30 and that the frame thereupon automatically receives a dolly with a filled barrel 40.

The foremost (rightmost) hale 2 on the belt 8 is urged against the ascending stretch of the belt 3 whereby the latter removes tobacco leaves 15 and transports them to the station accommodating the magazinc 17. Asstatcd=beforc the magazine 17 is preferably designed to hold a relatively small determinate supply 18 of loosened tobacco leaves or particles. The rate at which the belt 3 withdraws tobacco leaves from the foremost bale 2 on the belt 8 is monitored indirectly by the detector including the photosensitive receiver 19. When the upper level of the supply 18' in the magazine 17 reaches a predetermined plane, the light source can not transmit light rays to the receiver 19 whereby the latter discontinues the generation of a signal which causes completion of the circuit of the motor 14. i.c.. the motor 14 is arrested in response to deenergization of the relay 23 whose contact 23a is in the motor circuit. The motor 25 continues to drive the belt 29 of the evacuating conveyor 24 so that the left-hand stretch of the belt 29 removes tobacco leaves 15 from the magazine 17 whereby the supply 18 of leaves decreases and the light is again free to reach the receiver 19. This re ceiver then effects energization of the relay 23 and closing of the Contact 23a with a delay which is determined by setting of the time delay device 21. The latter is provided for the purpose of preventing starting and stoppage of the motor 14 in response to minor fluctuations in position of the upper level of tobacco supply 18 in the magazine 17. The magazine 17 receives fresh tobacco leaves 15 as soon as the relay 23 completes the circuit of the motor 14. The speeds of the belts 3 and 29 are selected in such a way that. when the motor 14 is running, the belt 3 delivers to the magazine 17 tobacco leaves 15 at a rate which exceeds the rate at which the belt 29 removes tobacco from the magazine i.e.. the upper level of thesupply 18 in the magazine 17 begins to rise in response to starting of the motor 14. This motor constitutes a regulating means which controls the operation of the removing conveyor 1 a function of the results of measurements carried out by the monitoring device including the photosensitive recciver.

FIG. 2 shows a second apparatus which comprises a monitoring device 141 for the tobacco stream 120. This monitoring device 141 forms part of a second con trol unit 142 which regulates the speed of the motor for the endless carded belt 129 of the evacuating conveyor 124. The monitoring device 141 is a weighing device which includes an endless conveyor belt 141a serving to transport the tobacco stream 120 to the neceiving conveyor 131 and having an upper stretch (measuring station) located at a level above a vertically movable detector 145. The second control unit 142 further comprises a transducer 143 which converts mechanical signals furnished by the detector 145 into electric signals and transmits such signals to a preamplifier 144. The latter transmits signals to a second am plifier 146 which is in circuit with the motor l25. The intensity of signals produced by the transducer 143 is a function of the extent of downward displacement of the detector 145. The second amplifier 146 is preferably a thyristor amplifier with an output which emits d-c signals. Such amplifiers are known in the art for example, under the name MlNl SEMl (produced by the West German firm AEG).

All other parts of the apparatus shown in FIG. 1 are identical with or clearly analogous to the corresponding parts of the apparatus shown in FIG 1; they are denoted by similar reference numerals plus 100.

The operation of the apparatus shown in H6. 2 is as follows:

The feeding unit 132 delivers bales 102 onto the upper stretch of the belt 108, when necessary. and the belt 108 maintains the foremost bale in the path of movement of spikes 107 on the belt 103. The latter removes from the bales 102 tobacco leaves 115 which are deposited in the magazine 117 and the upper level of the resulting determinate supply 118 is scanned by the photosensitive detector including the receiver 119. The control unit 116 effects intermittent operation of the d-c motor 114 in a manner as described in connection with the motor 14 of FIG. 1. The control unit 142 regulates the operation of the motor 125 as a function of the quantity of tobacco leaves 115 in successive increments of the stream 120 on the upper stretch of the belt 141a. The operation of the control unit 142 is such that the belt 129 of the evacuating conveyor 124 removes from the magazine 117 a uniform quantity of tobacco leaves per given length of time. i.e., that the average quantity of tobacco leaves 115 in the stream 120 is constant. For example, it can happen from time to time that the belt 129 withdraws from the magazine 117 a batch of coherent tobacco leaves which are dumped onto the upper stretch of the belt 141a. The control unit 142 then reduces the speed of the motor 125 (or brings it to a full stop) until the batch of coherent leaves is caused to advance beyond the weighing device 141 and the belt 141a again begins to receive tobacco leaves at a substantially constant rate. Analogously, the best 129 is accelerated if the stream 120 is interrupted due to a cavity in the supply 118 or when the quantity of tobacco in one or more increments of the stream 120 is less than desired. An important advantage of the apparatus shown in FIGv 2 is that it can detect variations in the rate at which the tobacco leaves 115 are being evacuated from the magazine 117, particularly longerlasting variations which are normally due to changes in the type size or condition of tobacco leaves.

The apparatus of FIG. 3 constitutes a modification of the apparatus shown in FIG. 2 and embodies certain features of both previously described apparatus. The feeding unit 232 is constructed in the same way as shown for the unit 32 of FIG. I. and the bale breaking or removing conveyor 201 is similar to the conveyor 1. However, the drive for the belts 203. 208 of the conveyor 201 is regulated by a control unit 252 which includes a monitoring device 251 corresponding to the monitoring device 14 with the exception that the magazine 117 is omitted and that the endless belt 251:! of the device 251 is disposed immediately downstream of the belt 203 so that it replaces the magazine 117. Thus. the stream of tobacco leaves 215 which are removed from the foremost bale 202 is caused to advance directly onto the upper stretch of the belt 2514: where the weight of its increments is measured by a vertically movable detector 255 cooperating with a transducer 253 corresponding to the transducer 143 of FIG. 2. The transducer 253 transmits signals to the motor 214 (which is a variable-speed Ll-C motor] by way of a pre amplifier 254 and a second amplifier 256; the latter preferably corresponds to the amplifier 145 of FIG. 2. All remaining parts of the apparatus shown in FIG. 3 are analogous to or identical with the corresponding parts ofthe apparatus shown in FIG I and are denoted by similar numerals plus 200.

TH E OPERATION The feeding unit 232 delivers bales 202 (when necessary) onto the belt 208 which advances the bales into the range of spikes 207 on the belt 203. The resulting stream of tobacco leaves 215 is transported upwardly and descends onto the belt 2511: so that the position of the detector 255 is a function of the weight of successive increments of the tobacco stream. The transducer 253 produces electric signals whose intensity is a function of the position of the detector 255. and such sig nals are amplified and utilized to regulate the motor 214. The regulating action of the control unit 252 is such that the average rate of withdrawal of tobacco leaves from the station above the belt 208 is constant.

Referring to FIG. 4. there is illustrated an apparatus which constitutes a further modification of the apparatus shown in FIG. 2. This apparatus comprises a modified monitoring or weighing device 341 which measures the weight of successive increments of the tobacco stream 320. The manner in which the feeding unit 332 delivers bales 302 to the belt 308 of the removing conveyor 301, and the manner in which the belt 303 of the conveyor 30] supplies tobacco leaves 315 to the magazine 317 is the same as described in connection with FIG. I or 2. The evacuating conveyor 324 corresponds to the conveyor 124 excepting that the control unit which regulates the speed of the motor 325 is different from the control unit 142. The detector 362 of the monitoring device 341 is an arm one end of which is mounted on a fixed horizontal pivot member 361 and the other end of which is coupled to a helical spring 363 which tends to pivot the detector arm 362 in a counterclockwise direction as viewed in FIG. 4. The pivot 361 is adjacent to the path in which the tobacco leaves 315 of the stream 320 descend onto the upper stretch of the endless bclt 3411:. The detector 362 arm constitutes the movable contact of a potentiometcr 364 which constitutes a transducer because it converts the mechanical signals (pivotal movements of the detector arm 362) into electrical signals. The motor 325 is a variable-speed d-c motor and drives a signal generator here shown as a conventional tachometer generator 366 which is designed to supply signals whose intensity is a function of rotational speed of the motor 325. The potentiometer 364 is in circuit with a variable resistor 367 and with an energy source 368 which delivers current at a constant potential. The control unit for the motor 325 further comprises a conventional integrator circuit 365 which receives signals from the tachometer generator 366 (indicating the speed of the motor 325] and from the potentiometer 364 (indicating the weight of successive increments of the tobacco stream 320). A suitable integrator circuit is disclosed, for example. on pages 1 179-1190 ofTaschenbuch der Naehrichtenverarbeitung by K. Steinbuch, published in 1962 by Springer Verlag of West Germany. The output signal of the integrator circuit 365 is transmitted to a signal comparing circuit 370 which compares the thus received signal with the signal from a rated value setting device 372, e.g. a potenti ometer which is adjustable by hand so as to supply to the circuit 370 a signal which is indicative of the de sired rate of tobacco withdrawal from the magazine 317. The output of the circuit 370 is connected with an amplifier 369 which is in circuit with the motor 325. The signal which is transmitted by the amplifier 369 is a function of the product of signals received from the tachometer generator 366 and monitoring device 34].

The amplifier 369 and the circuit 370 together consti tale a regulating device for the motor 325.

The endless belt 341a of the monitoring device 341 is driven by the belt 329 of the conveyor 324 by way of a belt or chain transmission 371. Thus. the speed at which the stream 320 is transported above the detector arm 362 increases or decreases in response to increas ing or decreasing speed of the belt 329.

THE OPERATION The feeding unit 332 delivers bales 302 to the belt 308 and the belt 303 removes tobacco leaves 315 from the foremost bale to deliver such leaves into the magazine 317 which accumulates a determinate supply 318. The level of the supply 318 is monitored by the detector including the photosensitive receiver 319 which forms part of the control unit 316 and effects intermit tent operation of the motor 314. The belt 329 of the evacuating conveyor 324 withdraws tobacco leaves 315 from the magazine 317 whereby such leaves form a stream 320 which descends onto the belt 341:! of the monitoring device 341 at a point close to the pivot member 36] for the detector arm 362. Such positioning of the pivot member 361 insures that the dynamic forces which develop when the tobacco leaves impinge on the upper stretch of the belt 341a have little or no effect on the accuracy of the monitoring device 341. Each successively delivered increment of the tobacco stream 320 causes the arm 362 to produce a basic signal when it reaches the belt 341a, and such increment then advances from the pivot member 361 toward the free end of the detector arm 362 (the length of the arm 362 determines the length of the measuring station). The influence of such increment on the angular posi tion of the arm 362 increases as the increment approaches the spring 363. i.e.. the basic signal undergoes gradual intensification. The angular position of the arm 362 at the time when a given increment reaches its righthand end is a function of the weight ofsuch increment. and the potentiometer 364 furnishes a corresponding signal which is transmitted to the integrator circuit 365. The potential at the output of the circuit 365 corresponds to a product of the signal indicating speed of the belt 341a (tachometer generator 366) and the signal indicating the extent of angular displacement of the detector arm 362. The resulting signal is transmitted to the signal comparing circuit 370 which also receives a signal from the potentiometer 372. The signal produced by the circuit 370 is indicative of the dif fcrence between the intensities of signals from the potentiometer 372 and integrator circuit 365. and such signal is employed to regulate the speed of the motor 325 so that the average quantity oftobaceo leaves 315 in the stream 320 remains constant. For example. if the quantity of tobacco per unit length of the stream 320 on the belt 341a increases. the slider of the potentiometer 364 (detector arm 362) changes its position and the amplifier 369 causes the motor 325 to receive cur rent in such a way that the speed of the belts 329 and 341a is reduced. If the quantity of tobacco leaves 315 per unit length of the stream 320 on the belt 341a is less than desired, the speed of the motor 325 increases so that the latter increases the speed of the belts 329 and 341a.

An important advantage of the apparatus shown in FIGS. 1 to 4 is that they are capable of rapidly converting accumulations or bales of compacted tobacco leaves into a stream of tobacco wherein each increment contains the same or nearly the same quantity of leaves. It was found that such apparatus are particularly suited for breaking of bales which contain Virginia or Burley 5 tobacco. A specific advantage of apparatus shown in FIG. I is that it comprises a single and relatively simple control unit 16 which carries out indirect measurements of the quantity of tobacco leaves which are removed by the belt 3 of the conveyor 1. This apparatus does not embody means for monitoring the quantity of tobacco in successive increments of the stream 20.

The apparatus of FIG. 2 is somewhat more complicated because it comprises two control units 116 and 142. However. it is capable of compensating for such characteristics of tobacco which cannot be considered by the control unit 116. Thus. the uniformity of the stream which reaches the receiving conveyor 13] is more satisfactory than the uniformity of the stream on the receiving conveyor 31 of FIG. 1. This apparatus can compensate for short-lasting as well as longer-lasting changes in the quantity of tobacco per unit length of the stream.

The apparatus of FIG. 3 constitutes a simplification of the apparatus of FIG. 2 and can be employed with particular advantage where the space is at a premium. The control unit 252 insures the formation of a uniform tobacco stream (receiving conveyor 231 An advantage ofthc apparatus shown in FIG. 4 is that it is even more accurate than the apparatus of FIG. 2; also. its operation can bereadily programmed. for example. by changing the setting of the potentiometer 372 in accordance with a predetermined schedule.

FIG. 5 illustrates a further apparatus which serves as a distributor for tobacco leaves and comprises a feeding unit having a hopper 401. at removing conveyor 448 and a magazine 430. The hopper 401 accommodates a substantial supply 402 of tobacco leaves which are not condensed. The removing conveyor 448 and the magazinc 430 together form an assembly 403 which serves to accumulate a relatively small determinate store or supply 404 of tobacco leaves in the magazine 430. An evacuating conveyor 406 removes from the lower zone 407 of the supply 404 a preferably continuous and most preferably uniform stream 405 which descends onto the endless belt 416 of a monitoring device 414. The evacuating conveyor 406 comprises an endless belt 411 which is trained over rollers 408. 409. The drive means for the evacuating conveyor 405 comprises an electric d-c motor 412.

The monitoring device 414 forms part of a control unit 413 which regulates the speed of the motor 412. The belt 416 of the monitoring device 414 is driven by an electric motor 415. The detector 417 of the monitoring device 414 is operatively connected with the slider 418 ofa potentiometer 419 which is a transducer and serves to transmit electric signals to a junction or signal comparing circuit 426. The intensity of the signal furnished by potentiometer 419 is a function of the weight of the corresponding increment of the tobacco stream 405 on the belt 416. The control unit 413 further comprises a regulating device 421 which is in circuit with the motor 412 and receives signals from the circuit 426. The purpose of adjustments of the speed of the motor 412 is to insure that the evacuating conveyor 406 removes a uniform stream 405, i.e.. that the combined weight of tobacco leaves removed from the supply 404 in the magazine 430 per unit of time is always the same. The regulating device 421 comprises a circuit 422 which includes a preamplifier 423 and a second amplifier 424 which is a magnet amplifier and supplies current to the armature winding of the d-c motor 412. It is clear that the amplifier 424 can be replaced with an amplifier having regulatable rectifier elements, such as thyristors. The aforementioned MlNlSEMl of the Firm AEG constitutes one form of an amplifier which can be utilized as a substitute for the amplifier 424. The signal comparing circuit 425 receives signals from the aforementioned potentiometer 419 and from the output 427 of a rated value setting device 428, e.g.. a manually adjustable potentiometer which is in circuit with an energy source. The circuit 426 compares the two signals and transmits to the preamplifier 423 a signal whose intensity is indicative of the difference between the intensities of signals from the

potcntiometers

419 and 428.

The electric circuit 431 of the assembly 403 is a twopoint regulating circuit and incudes two

photosensitive detectors

432, 433 mounted at different levels in the magazine 430 so as to supervise the height of the supply 404. The

detectors

432, 433 respectively constitute minimum and maximum level indicators and respectively comprise

light sources

434, 436 and

photosensitive receivers

437, 438 connected with

time delay devices

439, 441. These time delay devices are respectively connected with signal storing devices 442. 443 having storing inputs a and erasing inputs 1). The outputs of the storing

devices

442, 443 are connected to separate windings ofa relay 444 which is in circuit with a further relay 446. The relay 446 is in circuit with a reversible-pole asynchronous electric motor 447 which drives the roller 449 of an endless carded belt 452 forming part of the removing conveyor 448. The belt 452 is further trained over a roller 45] and is provided with spikes which transport tobacco leaves from the hopper 401. An endless belt 453 of the removing conveyor 448 furnishes tobacco leaves into the range of spikes on the belt 452. The contacts a of the relay 446 are in circuit with the higherpole number winding of the motor 447 (lower rotational speeds) and the contacts h of the relay 446 are in circuit with the lowerpole number winding of the motor 447 (higher rotational speeds). The source of polyphase current for the motor 447 is shown as 445.

THE OPERATION The accumulation of relatively small determinate supply 404 of tobacco leaves in the magazine 430 is regulated by the circuit 431 which increases the rate of tobacco delivery by the evacuating conveyor 448 when the level of tobacco in the magazine descends to a lower level (indicator 432) and increases the rate of tobacco delivery by the evacuating conveyor when the level of tobacco in the magazine rises to an upper level (indicator 433 J. This insures that the level of the supply 404 always fluctuates within a predetermined range. In FIG. 5. the level of the supply 404 is shown as being located between the levels of the

indicators

432 and 433. The signal storing device 443 emits a signal which energizes the winding (1 of the relay 444 whereby the relay 444 closes its contact t'. This energizes the relay 446 whose contacts :1 connect the corresponding windings of the motor 447 with the energy source 445. The motor 447 rotates at a lower speed so that the rate at which the removing conveyor 448 delivers tobacco leaves to the supply 404 is less than the rate at which the leaves are removed by the evacuating conveyor 406. Thus, the supply 404 of tobacco leaves in the magazine 430 decreases gradually until the level of tobacco leaves reaches the lower indicator 432. The latter produces a signal as soon as its light source 434 can direct light rays onto the photosensitive receiver 437, and such signal is transmitted to the input a of the signal storing device 442. The device 442 sends a signal to the input I) of the signal storing device 443 whereby such signal erases the output signal of the device 443. At the same time the signal storing device 442 sends an output signal to the winding b of the relay 444 whereby such signal causes deenergization of the relay 444 and opening of the latters contact c The relay 446 is deenergized whereby its contacts b connect the corresponding windings of the motor 447 with the energy source 445. The motor 447 then rotates at a higher speed so that the removing conveyor 446 delivers to the magazine 430 tobacoo leaves at an increased rate which suffices to gradually increase the supply 404 until the upper level of such supply reaches the upper indicator 433. The signal storing device 442 continues to emit an output signal until such output signal is erased in response to a signal to the input :1 of the device 443.

The upper indicator 433 emits a signal when the light rays issuing from the light source 436 cannot reach the receiver 438, and such signal is communicated to the input a of the signal storing device 433 by way of the delay device 441. As explained above. a signal at the input a of the signal storing device 433 results in generation of a signal which is transmitted to the input h of the storing device 442 and causes the latter to erase its output signal to the winding h of the relay 444. The relay 446 is dcenergizcd when the output of the signal storing device 433 sends a signal to the winding u of the relay 444. i.e. such signal causes the contact c of the relay 444 to close and to close the contacts u of the relay 446. The motor 447 then drives the removing conveyor 448 at a reduced speed so that the supply 404 in the magazine 430 again decreases. The same procedure is repeated when the level of the supply 404 descends to the level of the lower indicator 432. It will be seen that the quantity of tobacco in the supply 404 continuously fluctuates betwccn a maximum level (indica tor 433) and a minimum level (indicator 432). The purpose of the

time delay devices

439, 441 is to insure that the tobacco leaves which descend from the roller 449 onto the leaves in the supply 404 cannot cause unintentional generation of signals by the

indicators

432 and 433.

The removal of tobacco leaves from the magazine 430 is carried out as follows: The belt 411 of the evacuating conveyor 406 removes tobacco leaves from the lowermost zone 407 of the supply 404. The resulting stream 405 is fed onto the belt 416 of the monitoring device 414 and its increments travel at a level above the detector 417 whose position is thus a function of the weight of such increments. Unless the conditions change. the weight of successive increments of the stream 405 varies very little or not at all. The potcnti ometer 419 emits signals whose intensity is indicative of the weight of successive increments of the stream 405, and such signals are communicated to the signal comparing circuit 426. The latter also receives signals from the output 427 of the potentiometer 428, such signals indicating the desired weight of successive incremerits of the tobacco stream. The output signal of the circuit 426 is indicative of the difference between the intensities of signals from the

potentiometers

419 and 428, and such signal is transmitted to the preamplifier 423 of the circuit 422. The amplifier 424 regulates the speed of the motor 412 in such a way that the rate at which the belt 411 withdraws tobacco leaves from the magazine 430 remains within a desired range. Thus, if the weight of an increment of the stream 405 on the belt 416 of the monitoring device 414 is greater than desired. the circuit 422 slows down the motor 412 so that the quantity of tobacco leaves which are removed from the magazine 430 per unit of time is reduced accordingly. lnversely, the speed of the motor 412 is increased in the weight of increments of the stream on the belt 411 is less than desired.

The apparatus of FIG. 5 can be utilized with advantage for removal of stripped tobacco leaves. for removal of tobacco ribs or for removal of unstripped tobacco leaves. i.e.. of leaves which contain ribs and tobacco leaf laminae. It can be employed in all instances where tobacco leaves. laminae and/or ribs must be supplied at a constant rate for further processing. for ex ample, to a moistening or drying station. to a station where the tobacco is treated by addition offlavoring or other substances. to a heating station or the like. Fur thermore. the apparatus can be utilized to deliver tobacco to a mixing or blending station where the leaves. laminae and/or ribs are blended with one or more additional tobacco types. It is further clear that the appara tus can be provided with suitable programming means; for example. with programming means which adjusts the potentiometer 428 at desired intervals to thus change the average rate of tobacco delivery in accor dance with a predetermined schedule. The provision of a programming system is often desirable when the ap paratus is employed to furnish tobacco leaves. ribs and- ;or laminae to a blending station. Thus. the rate of tobacco delivery can be changed automatically in order to produce a different blend or to compensate for a change in the rate of delivery of other type of types of tobacco.

Referring finally to FIG. 6. there is shown an apparatus which can be utilized with advantage as a distribu tor for shredded tobacco. Uniform distribution of shredded tobacco presents problems because the shreds tend to adhere to and to become intertwined with each other. Such problems are particularly acute whenn the shredded tobacco is to form a narrow stream which is thereupon wrapped to form a cigarette rod. Satisfactory homogeneousncss of a narrow stream of shredded tobacco is an important prerequisite for the production of cigarettes whose weight is the same or whose weight fluctuates within a narrow range. The distributor of FIG. 6 is incorporated into or combined with a customary rod cigarette machine which is not shown in the drawing. This distributor comprises a feeding unit having a hopper 501 for a substantial supply 502 of shredded tobacco. The removing conveyor 548 is different from the conveyor 448 of FIG. 5; the carded belt 452 is replaced with a carded drum 560 which cooperates with a carded refuser drum S62 and with a picker roller 56]. The purpose of the refuser drum 562 is to remove from the carding of the drum 560 a surplus of tobacco shreds so that the drum 560 withdraws a continuous carpet of tobacco shreds which are removed from its spikes by the picker roller 561 Ill till

whereby the resulting shower of tobacco shreds descends in a magazine 530 to form a relatively small determinate supply 504.

The apparatus of FIG. 6 also comprises a two point regulating circuit which includes a minimum level indicator having a photosensitive receiver 532 and a maximum level indicator having a photosensitive receiver 533. The remaining elements of the regulating circuit are similar to or identical to the elements of the circuit 431 and are not shown in FIG. 6.

An evacuating conveyor 506 is provided to move to bacco shreds from the lower zone 507 of the supply 504 and to form a tobacco stream or carpet 505 which is fed onto the upper stretch of a belt 567 forming part of a monitoring or weighing device 514. The evacuating conveyor 506 comprises a driven carded drum 564 which cooperates with a smoothsurfaced refuser 56411 and with a picker roller 566. the latter serving to remove shreds from the spikes of the drum S64 and to cause the formation of the stream 505. The remaining parts of the monitoring device 514 are similar to or identical with the parts of the monitoring device 414; this monitoring device 514 forms part of a control unit which is analogous to the control unit 413 of FIG. 5. The purpose of such control unit is to regulate the speed of the drum 564 by way of a drive including a variablwspecd motor corresponding to the motor 412 of FIG. 5.

The discharge end of the belt 567 showers the leading edge of the stream 505 into a narrow channel 569 formed by a travelling belt 568 which transports the resulting narrow stream of shredded tobacco to a wrap ping station (not shown) where the stream is enclosed in a tape of cigarette paper or the like to form a wrapped tobacco rod.

The aforementioned two-point regulating circuit which includes the receivers 532. 533 in the magazine 530 insures that the level ofthe supply 504 in the magazine invariably remains within a desired range. and the control unit including the monitoring device 514 insures that the speed of the carded drum 564 of the evacuating conveyor 506 changes when the weight of increments of the stream 505 on the upper stretch of the belt 567 deviates from a desired weight.

THE OPERATION:

The two-point regulating circuit insures that the level of the supply 504 in the magazine 430 does not rise above the level of the upper receiver 533 or decrease below the level of the lower receiver 532. The carded drum 564 continuously withdraws a substantially constant quantity of tobacco shreds from the lower Zone 507 of the supply 504. and the picker roller 566 showers the withdrawn shreds to form the stream 505 whose increments are weighed on the upper stretch of the endless belt 567. The speed of the drum S64 is regulated by the control unit which includes the monitoring device 514. The narrow stream of tobacco shreds in the channel 569 of the travelling belt 568 may (but need not) be trimmed prior to wrapping into cigarette paper or other wrapper material. The resulting tobacco rod is thereupon severed at regular intervals to form wrapped tobacco rodsections of unit length or multiple unit length.

It was found that the uniformity of the stream which is produced in the apparatus of FIGS. 5 and 6 is due. to a considerable degree. to the fact that the magazine 430 or 530 contains a predictable

determinate supply

404 or 504 of tobacco leaves or shreds, i.c., that the level of such supply does not fluctuate beyond a predetermined range. The control unit 413 (and the corresponding control unit of FIG. 6) serves as a means for insuring further equalization or uniformizing of the ultimate product, i.e.. to compensate for such factors which cannot be properly compensated for at an earlier stage of the stream formation. Such factors include the size of tobacco leaves or the size of parts of tobacco leaves, the nature of tobacco leaves, and the physical condition of treated material.

The monitoring or weighing

device

141, 251, 341, 414 or 514 can be replaced with a monitoring device which employs one or more capacitors. Such monitoring device is disclosed in US. Pat. No. 3,320,528 of Esenwein.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of my contribution to the art.

What is claimed as new and desired to be protected by letters patent is set forth in the appended:

l. A method of converting compacted tobacco into a continuous stream, comprising the steps of breaking up a bale of compacted tobacco by removing tobacco from said bale at a first station to form loose tobacco; conveying loose tobacco from the first station along a predetermined path, including transporting loose tobacco from said first station to a second station which is adjacent to said path, collecting the thus transported tobacco at said second station to form a determinate supply of loose tobacco and evacuating a stream of loose tobacco from said supply; measuring the quantity of tobacco at said second station, including measuring the quantity of tobacco in said supply; regulating the rate of removal of tobacco at said first station as a function of the result of measurement at said second station; measuring the quantity of tobacco per unit length of said stream at a third station downstream of said sec ond station; and regulating the evacuation of tobacco from said supply as a function of the measurement at said third station.

2. A method of converting a mass of tobacco into a continuous stream, comprising the steps of accumulat ing a first supply of tobacco which contains a determinate quantity of tobacco, including establishing a second supply of tobacco, transporting tobacco from said second supply to said first supply, measuring the quantity of tobacco in said first supply. and changing the rate of transport of tobacco from said second supply to said first supply when the measured quantity of tobacco forming said first supply is without a predetermined range; evacuating tobacco from said first supply and conveying the thus evacuated tobacco in the form of a stream of loose tobacco along a predetermined path; measuring the quantity of tobacco in successive increments of the stream in a predetermined portion of said path: and regulating the rate ofcvacuation of tobacco from said first supply as a function of the results of mcasuremcnts in said portion of said path.

3. Apparatus for converting bales or analogous masses of compacted tobacco located at at removing station into a substantially constant stream, comprising removing conveyor means operative to break up and loosen tobacco from bales of compacted tobacco at said removing station; control means including first monitoring means for measuring the quantity of removed loose tobacco and means for regulating the removal of loose tobacco by said removing conveyor means in accordance with the results of measurements by said first monitoring means; a magazine positioned to receive tobacco from said removing conveyor means and to accumulate such tobacco in the form of a determinate supply; variable-speed evacuating conveyor means for evacuating from said supply tobacco in the form ofa continuous stream; and second control means including second monitoring means for measuring the quantity of tobacco in successive increments of said stream and regulating means for changing the speed of said evacuating conveyor means when the quantity of tobacco in at least one of said increments is without a predetermined range.

4. Apparatus for converting bales or analogous masses of compacted tobacco located at a removing station into a substantially constant stream. comprising removing conveyor means operative to break up and loosen tobacco from bales of compacted tobacco at said removing station; control means including moni toring means for measuring the quantity of removed loose tobacco and means for regulating the removal of loose tobacco by said removing conveyor means in accordance with the results of measurements by said monitoring means; a magazine positioned to receive tobacco from said removing conveyor means and to accumulate such tobacco in the form of a determinate supply; and evacuating conveyor means for evacuating from said magazine tobacco in the form of a stream. said monitoring means being arranged to measure the quantity of tobacco in said supply.

5. Apparatus for converting a mass of tobacco into a continuous stream, comprising an assembly for forming a determinate supply of tobacco, said assembly including a magazine for said supply, a main source of tobacco and removing conveyor means operative to transport tobacco from said main source to said magazine; variable-speed evacuating conveyor means for evacuating from said supply tobacco in the form of a continuous stream of loose tobacco; first control means including monitoring means for measuring the quantity of tobacco in successive increments of the stream and regulating means for changing the speed of said evacuating conveyor means when the quantity of tobacco in at least one of said increments is without a predetermined range; and second control means including means for monitoring the quantity of tobacco in said supply and regulating means for changing the operation of said removing conveyor means when the quantity of tobacco in said supply is without a predetermined range.

6. A method of converting a mass of tobacco into a substantially uniform stream, comprising the steps of accumulating a supply of tobacco; withdrawing from said supply tobacco at a variable speed to form a continuous stream of loose tobacco and advancing said stream along a predetermined path in such a way that the weight of successive increments of said stream varies in a predetermined portion of said path in dependency on the changes in said speed; weighing said suc cessive increments of the stream in said predetermined portion of said path; producing first and second signals which respectively indicate the speed at which tobacco is being withdrawn and the weight of said successive increments; and utilizing such signals to change said speed when the weight of said increments at a particular speed is without a predetermined range.

7. A method as defined in claim 6, wherein said weighing step comprises advancing said successive increments of the stream along said predetermined portion of said path and wherein the step of producing said second signals comprises producing a basic signal whose intensity is proportional to the weight of the respective increment and thereupon gradually intensifying such signal while the respective increment advances along said predetermined portion of said path 8. A method as defined in claim 6. wherein said advancing step comprises transporting tobacco toward and in said predetermined portion of said path. and wherein the speed of transport of tobacco in said predetermined portion of said path is respectively in creased and reduced in response to an increase and reduction in the speed of tobacco transport toward said predetermined portion.

9. Apparatus for regulating the quantity of tobacco in a travelling tobacco stream of varying weight, comprising conveyor means for transporting a stream of loose tobacco lengthwise along a predetermined path; monitoring means including a weighing device having an elongated detector extending along a predetermined portion of said path and having a first end portion pivotable about a fixed axis and a second end portion located downstream of said first end portion, said conveyor means being arranged to advance successive in crements of said stream over and in a direction from the first toward the second portion of said detector whereby the latter tends to pivot about said axis to an extent which is a function of the weight of an increment and of the distance between such increment and said pivot axis. and means for regulating the speed of said conveyor means as a function of the angular position of said detector,

Claims

1. A method of converting compacted tobacco into a continuous stream, comprising the steps of breaking up a bale of compacted tobacco by removing tobacco from said bale at a first station to form loose tobacco; conveying loose tobacco from the first station along a predetermined path, including transporting loose tobacco from said first station to a second station which is adjacent to said path, collecting the thus transported tobacco at said second station to form a determinate supply of loose tobacco and evacuating a stream of loose tobacco from said supply; measuring the quantity of tobacco at said second station, including measuring the quantity of tobacco in said supply; regulating the rate of removal of tobacco at said first station as a function of the result of measurement at said second station; measuring the quantity of tobacco per unit length of said stream at a third station downstream of said second station; and regulating the evacuation of tobacco from said supply as a function of the measurement at said third station.

2. A method of converting a mass of tobacco into a continuous stream, comprising the steps of accumulating a first supply of tobacco which contains a determinate quantity of tobacco, including establishing a second supply of tobacco, transporting tobacco from said second supply to said first supply, measuring the quantity of tobacco in said first supply, and changing the rate of transport of tobacco from said second supply to said first supply when the measured quantity of tobacco forming said first supply is without a predetermined range; evacuating tobacco from said first supply and conveying the thus evacuated tobacco in the form of a stream of loose tobacco along a predetermined path; measuring the quantity of tobacco in successive increments of the stream in a predetermined portion of said path; and regulating the rate of evacuation of tobacco from said first supply as a function of the results of measurements in said portion of said path.

3. Apparatus for converting bales or analogous masses of compacted tobacco located at a removing station into a substantially constant stream, comprising removing conveyor means operative to break up and loosen tobacco from bales of compacted tobacco at said removing station; control means including first monitoring means for measuring the quantity of removed loose tobacco and means for regulating the removal of loose tobacco by said removing conveyor means in accordance with the results of measurements by said first monitoring means; a magazine positioned to receive tobacco from said removing conveyor means and to accumulate such tobacco in the form of a determinate supply; variable-speed evacuating conveyor means for evacuating from said supply tobacco in the form of a continuous stream; and second control means including second monitoring means for measuring the quantity of tobacco in successive increments of said stream and regulating means for changing the speed of said evacuating conveyor means when the quantity of tobacco in at least one of said increments is without a predetermined range.

4. Apparatus for converting bales or analogous masses of compacted tobacco located at a removing station into a substantially constant stream, comprising removing conveyor means operative to break up and loosen tobacco from bales of compacted tobacco at said removing station; control mEans including monitoring means for measuring the quantity of removed loose tobacco and means for regulating the removal of loose tobacco by said removing conveyor means in accordance with the results of measurements by said monitoring means; a magazine positioned to receive tobacco from said removing conveyor means and to accumulate such tobacco in the form of a determinate supply; and evacuating conveyor means for evacuating from said magazine tobacco in the form of a stream, said monitoring means being arranged to measure the quantity of tobacco in said supply.

6. A method of converting a mass of tobacco into a substantially uniform stream, comprising the steps of accumulating a supply of tobacco; withdrawing from said supply tobacco at a variable speed to form a continuous stream of loose tobacco and advancing said stream along a predetermined path in such a way that the weight of successive increments of said stream varies in a predetermined portion of said path in dependency on the changes in said speed; weighing said successive increments of the stream in said predetermined portion of said path; producing first and second signals which respectively indicate the speed at which tobacco is being withdrawn and the weight of said successive increments; and utilizing such signals to change said speed when the weight of said increments at a particular speed is without a predetermined range.

7. A method as defined in claim 6, wherein said weighing step comprises advancing said successive increments of the stream along said predetermined portion of said path and wherein the step of producing said second signals comprises producing a basic signal whose intensity is proportional to the weight of the respective increment and thereupon gradually intensifying such signal while the respective increment advances along said predetermined portion of said path.

8. A method as defined in claim 6, wherein said advancing step comprises transporting tobacco toward and in said predetermined portion of said path, and wherein the speed of transport of tobacco in said predetermined portion of said path is respectively increased and reduced in response to an increase and reduction in the speed of tobacco transport toward said predetermined portion.

9. Apparatus for regulating the quantity of tobacco in a travelling tobacco stream of varying weight, comprising conveyor means for transporting a stream of loose tobacco lengthwise along a predetermined path; monitoring means including a weighing device having an elongated detector extending along a predetermined portion of said path and having a first end portion pivotable about a fixed axis and a second end portion located downstream of said first end portion, said conveyor means being arranged to advance successive increments of said stream over and in a direction from the first toward the second portion of said detector whereby the latter tends to pivot about said axis to an extent which is a function of the weight of an increment and of the distance between such increment and said pivot axis, and means for regulating the speed of said conveyor means as a function of the angular position of said detector.